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Resources for Algebra •• B-1 •• Public Schools of North Carolina
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Resources for Algebra •• B-2 •• Public Schools of North Carolina
Resources for Algebra •• B-3 •• Public Schools of North Carolina
Resources for Algebra •• B-4 •• Public Schools of North Carolina
Resources for Algebra •• B-5 •• Public Schools of North Carolina
Resources for Algebra •• B-6 •• Public Schools of North Carolina
Resources for Algebra •• B-7 •• Public Schools of North Carolina
Resources for Algebra •• B-8 •• Public Schools of North Carolina
Resources for Algebra •• B-9 •• Public Schools of North Carolina
Resources for Algebra •• B-10 •• Public Schools of North Carolina
Resources for Algebra •• B-11 •• Public Schools of North Carolina
Creating "Real World" Problems
When hurricane Fran hit North Carolina on the evening of September 5, 1996, over one million homes
and businesses were left without power. On September 14, The News & Observer of Raleigh displayed
the following information in the form of a graph.
Date Customers without power
Sept. 6 1,159,000
Sept. 7 804,000
Sept. 8 515,000
Sept. 9 340,500
Sept. 10 195,200
Sept. 11 136,300
Sept. 12 77,000
Sept. 13 37,600
Take advantage of the information provided and create problems related to topics you are presently
studying. Use them for classwork, homework, or quiz/test items. Here are some possibilities.
♦ Make a scatterplot of the data and discuss any patterns or trends apparent. Estimate when all power
would be restored.
♦ Based on the initial number of customers without power, what percent of those customers had their
power restored after one day? after two days? after three days?
♦ Using only the September 6 and 7 data, create a linear equation and use it to predict when all of the
customers would have their power restored.
♦ Find the equation of the best-fit curve (linear or exponential) and use it to predict when all of the
customers would have their power restored.
Resources for Algebra •• B-12 •• Public Schools of North Carolina
Mathematician Project
I. Select a mathematician from the list provided. The name of the mathematician that you select is
due on _____________________.
Total points (5 max) _______________.
II. Take a large sheet of construction paper and fold it in half.
A. Design a neat and original (10 points) cover for your book. The following should be on
your cover:
1. Name of the mathematician 5 points
2. Some aspect of their life or work 5 points
3. Color 5 points
4. Your name as author 5 points
Total points (30 max) _______________.
B. The first inside page should be in ink or typed (5 points) and have:
1. Your name 5 points
2. File number 5 points
3. Class period 5 points
4. Name of mathematician 5 points
5. List of sources of information 5 points
Total points (30 max) _______________.
C. The other inside pages are the report on the mathematician which should be written
in ink or typed (5 points) and should include the following:
1. Personal information about the mathematician
such as nationality and dates lived 10 points
2. His or her contribution to mathematics 10 points
3. Other interesting information 10 points
Total points (35 max) _______________.
The project is due __________________.
Late projects will not be accepted !!!!
Resources for Algebra •• B-13 •• Public Schools of North Carolina
Add 5.
Double the result.
Subtract 4.
Divide by 2. (Take half.)
Subtract the number you
started with
The result is ...
Choose a number.
Number Tricks
Resources for Algebra •• B-14 •• Public Schools of North Carolina
Basketball
Recording Sheet
Names______________________________ Date __________
______________________________ Period __________
1. ________ 14. ________
2. ________ 15. ________ Frequency Table
3. ________ 16. ________ 0 points ________
4. ________ 17. ________ 1 point ________
5. ________ 18. ________ 2 points ________
6. ________ 19. ________
7. ________ 20. ________ Total points scored ______________
8. ________ 21. ________ Average points
scored per game _____________
9. ________ 22. ________
FT Shooting Percent ____________
10. ________ 23. ________
11. ________ 24. ________
12. ________ 25. ________
13. ________
————————————————————————————————————————————————————
Class Frequency Table
0 points ___________ Total points scored _______________
1 point ___________ Average points scored _____________
2 points ___________ FT Shooting Percent _______________
Resources for Algebra •• B-15 •• Public Schools of North Carolina
Basketball Extension 1: How good is your player?
Focus: Graph and use linear equations.
Review: Work with ratios, proportions, and percents.
Goal:
The students will simulate the free throw situation de-
scribed in With the game on the line ... for different
players on the Charlotte Bobcats roster (or use players of
your own choosing). The students will determine whether
there are any patterns exhibited in their results.
Materials:
Recording sheets (B-16), Charlotte roster (B-17), graph paper, calculators.
Description:
Students, working in pairs, are going to simulate the end-of-game situation 50 times and keep a record
of their results. Students will use a random number generater (telephone book, calculator) to simulate
shooting free throws. Students will compare their experimental results and discuss which players they
would choose to be shooting free throws with the outcome of the game on the line. Students should be
able to discuss the relationship between the shooting percentage and average points scored.
Procedure:
Assign teams of students a player from the current Charlotte Bobcats roster (B-17). Have them record the
player’s name, FT (free throws made), and FTA (free throws attempted) on the recording sheet (B-16).
Compute FTMFTA
(shooting percentage) and record.
Have the students follow the same procedure they used in With the game on the line ...
Have each team report its player’s original shooting percentage ( FTMFTA
) and the average points scored.
Make a table of those results.
Example: FTMFTA
0.58 0.69 0.78 0.93
Avg points scored 1.19 1.35 1.51 1.93
Have the students graph the ordered pairs ( FTMFTA
, AvgPts) and describe any patterns apparent.
Have the students find a line of best fit (with or without a calculator). Determine the slope and
y-intercept and explain within the context of the problem.
Expect an equation approximating y = 2x, where x is the free throw percentage and y is the average
points scored. In the ideal situation where the slope is 2, we would say that the average points scored is
twice the shooting percentage.
MATHEMATICS
MATHEMATICS
Resources for Algebra •• B-16 •• Public Schools of North Carolina
FT Shooting Percent _______________
Recording Sheet
Names______________________________ Date __________
______________________________ Period __________
Player _______________ FT = ______ FTA = ______
FTFTA
= _________
1. ________ 14. ________ 26. ________ 39. ________
2. ________ 15. ________ 27. ________ 40. ________
3. ________ 16. ________ 28. ________ 41. ________
4. ________ 17. ________ 29. ________ 42. ________
5. ________ 18. ________ 30. ________ 43. ________
6. ________ 19. ________ 31. ________ 44. ________
7. ________ 20. ________ 32. ________ 45. ________
8. ________ 21. ________ 33. ________ 46. ________
9. ________ 22. ________ 34. ________ 47. ________
10. ________ 23. ________ 35. ________ 48. ________
11. ________ 24. ________ 36. ________ 49. ________
12. ________ 25. ________ 37. ________ 50. ________
13. ________ 38. ________
———————————————————————————————————————
Frequency Table
0 points ___________ Total points scored _______________
1 point ___________ Average points
scored per game _______________
2 points ___________
Basketball
Resources for Algebra •• B-17 •• Public Schools of North Carolina
20
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Resources for Algebra •• B-18 •• Public Schools of North Carolina
Basketball Extension 2: In theory, my player should ...
Focus: Use the language of algebra.
Review: Perform operations with real numbers.
Goal:
Determine theoretical probabilities for the various free throw shooting outcomes and relate average
points scored to the expected value function.
Materials:
Calculators and results from With the game on the line ... and How good is your player?
Description:
In With the game on the line ..., the students calculated an
average points scored. In probability, this result is called
the expected value. Direct teaching and Socratic
discussion should characterize this activity. Students
should have an adequate background in probability from
middle school mathematics.
Procedure:
According to the introductory problem, what was Curry’s chance of hitting a free throw? ( 146171 )
What was his chance of missing a free throw? (
25171)
Compare all of the following theoretical results with the experimental results from With the game on
the line ... and How good is your player?
Ask the students what has to happen to score 0 points? (MISS twice)
P0 = MISS•MISS = (
25171)•(
25
171) = .0214
Ask the students what has to happen to score 1 point? (HIT and MISS or MISS and HIT)
P1 = HIT•MISS + MISS•HIT = ( 146171 )•(
25
171) + (
25171)•(
146171 ) = .2496
Ask the students what has to happen to score 2 points? (HIT twice)
P2 = HIT•HIT = ( 146171 )•(
146171 ) = .7290
Point out to students that (chance of a HIT) + (chance of MISS) = 1 and P0 + P1 + P2 = 1. The sum of
all outcomes (chances) has to be 1, otherwise all possibilities are not accounted.
Expected Value = 0•P0 + 1•P1 + 2•P2 = 0•(0.0214) + 1•(0.2496) + 2•(0.7290) = 1.71
Have the students compare 1.71 with their team results and the class results from With the game on the
line ... Have the students calculate the expected value for their players from How good is your player?
and comment.
MATHEMATICS
MATHEMATICS
Resources for Algebra •• B-19 •• Public Schools of North Carolina
Basketball Extension 3: It really looks like algebra.
Focus: Perform operations with polynomials.
Review: Use the language of algebra.
Goal:
Use algebraic notation to generalize free throw shooting and explore the functions created.
Materials: Calculators and notes from In theory, my player should ...
Description:
Direct teaching and Socratic discussion of variables, polynomials, and theoretical probability as
it relates to the free throw shooting experiences should characterize this activity.
Procedure:
Using algebraic notation we can generalize free
throw shooting and accommodate any player’s
statistics. Let x be the probability of any player
hitting a free throw.
What is any player’s chance of missing a free
throw? (1-x)
For any player in the 2-shot free throw situation,
P0 = MISS•MISS = (1 - x)•(1 - x) = 1- 2x + x2
P1 = HIT•MISS + MISS•HIT = x(1 - x) + (1 - x)x = 2x(1 - x) = 2x - 2x2
P2= HIT•HIT = x•x = x2
Graph these probability functions. What are their domain and range?
Have the students compute the frequency at which their player scored 0, 1, and 2 points.
Evaluate the probability functions for their player and compare with their experimental results.
Recall, if Expected Value = 0•P0 + 1•P1 + 2•P2
= 0•(1 - 2x + x2) + 1•(2x - 2x2) + 2(x2)
= 2x
How good a free throw shooter does a player need to be in order to score at least 1 point in
a 2-shot situation?
Have students derive the probability functions for scoring 0, 1, 2 points, and expected value in
one-and-one and 3-shot free throw situations.
For one-and-one: P0 = 1 - x, P1= x - x2, P2 = x2, EV = x + x2
For 3-shot: P0 = 1 - 3x + 3x2 - x3, P1= 3x - 6x2 + 3x3, P2 = 3x2 - 3x3, P3= x3, EV = 3x
MATHEMATICS
MATHEMATICS
Resources for Algebra •• B-20 •• Public Schools of North Carolina
1. Krypto Hand Target Number ___________
Expression ____________________________________________________
2. Krypto Hand Target Number ___________
Expression ____________________________________________________
3. Krypto Hand Target Number ___________
Expression ____________________________________________________
4. Krypto Hand Target Number ___________
Expression ____________________________________________________
* Cards that are needed: three of each number 1 - 10; two of each number 11 - 17; and one of each number 18 - 25.
Krypto
• Each student should have a copy of this recording sheet.
• With a deck of Krypto cards*, deal five cards to each student and one target card for the
whole group.
• Record the five numbers that were dealt and the target number.
• Each student must use all five numbers and any operations to create an expression equal to
the target number.
Resources for Algebra •• B-21 •• Public Schools of North Carolina
Race To The Top
Resources for Algebra •• B-22 •• Public Schools of North Carolina
Race To The Top
Name ____________________
Resources for Algebra •• B-23 •• Public Schools of North Carolina
Race to the Top
Resources for Algebra •• B-24 •• Public Schools of North Carolina
Four In A Row
-20-24 -18 -16 -15 free
-12 -10 -9 -8 -6 -5
free -4 -3 -2 -1 1
2 3 4 5 6 8
9 10 12 15 16 18
20 24 free 25 30 36To play Four in a Row, you will need markers of two different shapes or colors and two paper clips.
Play begins by the first player placing the two paper clips on any pair of factors along the bottom edge
of the game board. The player then places a marker on the square which is the product of the two
factors. The next player is allowed to move exactly ONE clip and cover the square which is the product
of the two indicated factors. (Both clips can be placed on the same factor to square that factor.) Play
alternates until someone gets four markers in a row, horizontally, vertically, or diagonally.
-6 -5 -4 -3 -2 -1 1 2 3 4 5 6
Resources for Algebra •• B-25 •• Public Schools of North Carolina
Relays
1. Evaluate: 2 • 3 + 5 • 6 = __________
Put your answer in space #1.
2. Evaluate: 4 + 2(5 - 1) = __________
Add your answer to the quantity in space #1 and put the
result in space #2.
3. Evaluate: 2 • 32 = __________
Subtract your answer from the quantity in space
#2 and place the result in space #3.
4. Evaluate: 3 + 4(1 + 2) = __________
Multiply your answer by 2 and add it to the quantity
in space #3. Place your result in space #4.
5. Evaluate: 10 • 2 ÷ 5 + 15 = __________
Add your answer to the quantity in space #4 and
put the result in space #5.
6. Evaluate: 2(1 + 3)2 = __________
Subtract your answer from the quantity in Space #5
and put the result in space #6.
Relay Form
1. 4.
2. 5.
3. 6.
Resources for Algebra •• B-26 •• Public Schools of North Carolina
Relays
Relay Form
1. 4.
2. 5.
3. 6.
1.
2.
3.
4.
5.
6.
Resources for Algebra •• B-27 •• Public Schools of North Carolina
-6-5
-4-3
-2-1
01
23
45
6
1
2
3
45
YouOpponent
Totals
Round
Absolutely !!
1
2
3
45
You Opponent
Totals
Round
Absolutely !!
Resources for Algebra •• B-28 •• Public Schools of North Carolina
Patterns With Exponents
I. Make a table and fill in values using exponents 1 through 10 for bases 2, 3, 4, 5, ... , 10.
Use a spreadsheet or calculator.
On a spreadsheet, enter the exponents in Column A. The formula for base 2 would be =2^A2.
Enter this in B2 and then use filldown. For base 3, enter =3^A2, then filldown, etc.
On a calculator, enter y = 2x into the y= menu, look at the table to see the values. Continue and
enter y = 3x. Look at the table for the values, etc.
II. Using the table, answer the following:
1. What are the possible digits in the units place for base of 2?
2. What are the possible digits in the units place for base of 3?
3. Find all possible units digits for:
Base
4 _______________________________________
5 _______________________________________
6 _______________________________________
7 _______________________________________
8 _______________________________________
9 _______________________________________
10 _______________________________________
Resources for Algebra •• B-29 •• Public Schools of North Carolina
4. What would be the last digit of : (Use the above pattern)
a) 1025
b) 648
c) 215
d) 316
e) 925
5. Which is larger? 610
or 710
105 or 8
6
48 or 3
9
6. What base gives the following values:
B7 = 823,543; B=
B6 = 531,441; B=
B5 = 371,293; B=
7. What is the largest power of 2 that your calculator will display without using
scientific notation?
8. What is the last digit of 2450
?
From: Peters et al.. (1991). Patterns and Functions. Reston, VA: NCTM.
Resources for Algebra •• B-30 •• Public Schools of North Carolina
Number Crunching With Ease!
Scientific notation can make calculating with large and small numbers a breeze! In part A, complete the
applications from science. In part B, you will see how you can use scientific notation on a calculator to
solve problems.
A. 1. Our solar system is about 3 • 104 light years from the center of the Milky Way Galaxy. A light
year is a distance approximately 5.9 • 1012
miles. How many miles are we from the center of the
Milky Way?
2. A poliomyelitis virus is about .025 microns in length. A micron is 10-3
millimeters. Rewrite the
length of the virus in millimeters using scientific notation. If a microbiologist looks at the virus
with an electron microscope that magnifies by 104 times, what is the length of the image of the
virus observed?
3. A scientist is given a picture taken with an electron microscope that magnifies 104 times. She
needs to determine whether the microorganism is a yeast or bacterium. The width of the
organism in the photo is 48 millimeters. She knows that bacteria have a width approximately
0.5 microns while yeast are approximately 5 microns ( a micron is 10-3
millimeters). Is the
organism a yeast or bacterium? Explain how you can determine this?
4. Could a microbiologist use a light microscope that magnifies an image 1000 times to observe a
virus of length .04 microns? What would be the length in millimeters of the image of the virus?
Resources for Algebra •• B-31 •• Public Schools of North Carolina
B. Use a calculator to complete the following:
1. Most calculators cannot calculate a number as large as 5150
. How could you use scientific
notation and a calculator to calculate this number?
2. You are offered a job in which you are in training during the first year. Your boss offers to pay
you $.01 the first week, $.02 the second week, $.04 the third week, $.08 the fourth week, etc.
What would be the total amount that you would earn the first year?
a. Complete the table
Week Total Earned
1
2
3
4
5
b. Now, calculate and compare
21, 2
2 , 2
3, 2
4, 2
5
c. Write a formula to calculate the total earnings at the end of 52 weeks. Calculate
this answer on your calculator. Write the number in scientific notation and then in
expanded form.
Resources for Algebra •• B-32 •• Public Schools of North Carolina
Bull's Eye Score Sheet
Goal Number: __________
Round Result of Roll Operation Chosen Cumulative Total
(add or subtract) 0
1 ___________ ______________ _______________
2 ___________ ______________ _______________
3 ___________ ______________ _______________
4 ___________ ______________ _______________
5 ___________ ______________ _______________
6 ___________ ______________ _______________
7 ___________ ______________ _______________
8 ___________ ______________ _______________
9 ___________ ______________ _______________
10 ___________ ______________ _______________
11 ___________ ______________ _______________
12 ___________ ______________ _______________
13 ___________ ______________ _______________
14 ___________ ______________ _______________
15 ___________ ______________ _______________
16 ___________ ______________ _______________
Resources for Algebra •• B-33 •• Public Schools of North Carolina
In-Line Skating(Calories consumed per minute by weight and speed)
Speed (mph) 8 9 10 11 12 13 14 15
Weight (lbs.)
120 4.2 5.8 7.4 8.9 10.5 12.1 13.6 15.2
140 5.1 6.7 8.3 9.9 11.4 13.0 14.6 16.1
160 6.1 7.7 9.2 10.8 12.4 13.9 15.5 17.1
180 7.0 8.6 10.2 11.7 13.3 14.9 16.4 18.0
200 7.9 9.5 11.2 12.6 14.2 15.8 17.3 18.9
1965 1.5
1970 5.1
1976 11.0
1977 12.2
1978 13.4
1979 14.8
1980 17.7
1981 23.1
1982 29.3
1983 34.1
1984 37.3
1985 39.9
1986 42.2
Cable Subscribers(millions)
1987 45.0
1988 48.6
1989 52.6
1990 54.9
1991 55.8
1992 57.2
1993 58.8
1994 60.5
1995 63.0
1996 64.7
1997 65.9
1998 67.0
Data from the National Cable Television Association
Resources for Algebra •• B-34 •• Public Schools of North Carolina
Land Speed Records(MPH)
1906 127.659
1910 131.724
1911 141.732
1919 149.875
1920 155.046
1926 170.624
1927 203.790
1928 207.552
1929 231.446
1931 246.086
1932 253.96
1933 272.109
1935 301.13
1937 311.42
1938 357.5
1939 368.9
1947 394.2
1963 407.45
1964 536.71
1965 600.601
1970 622.407
1983 633.6
1997 763.035
Personal Fitness(calories used per minute by body weight)
Weight (lbs) 100 120 150 170 200 220
Running 9.4 11.3 14.1 16.0 18.8 20.7
(8 min miles)
Skiing 7.2 8.7 10.8 12.3 14.5 15.9
(cross country)
Jogging 6.1 7.3 9.1 10.4 12.2 13.4
(11 min miles)
Bicycling 5.4 6.5 8.1 9.2 10.8 11.9
(10 mph)
Walking 3.9 4.6 5.8 6.6 7.8 8.5
(15 min miles)
Skating 3.6 4.3 5.4 6.1 7.2 7.9
(moderate)
Swimming 5.8 6.9 8.7 9.8 11.6 12.7
Resources for Algebra •• B-35 •• Public Schools of North Carolina
Patterns in Perimeter
If each side of the first figure in each set has a length of one unit, what is the perimeter of the other
figures in each set? Fill in the table accompanying each set of figures.
1 2 3 4 5 10 n
1 2 3 4 5 10 n
1 2 3 4 5 10 n
1 2 3 4
I. Triangles
Perimeter
1 2 3 4
II. Squares
Perimeter
1 2 3 4
III. Hexagons
Perimeter
Resources for Algebra •• B-36 •• Public Schools of North Carolina
1 2 3 4 5 10 n
8 14 440
1 2 3 4
1 2 3 4
1 2 3 4 5 10 n
8 256
1 2 3 4 5 10 n
1 2 3
12 268
VII. Use or or a figure of your own
to make a sequence of shapes to be shared and analyzed.
IV. Octagons
Perimeter
V. 3-Squares
Perimeter
VI. T-Squares
Perimeter
Resources for Algebra •• B-37 •• Public Schools of North Carolina
If the length of each side of the triangle is one unit, what are the
perimeters of each of these figures?
perimeter =
perimeter =
perimeter =
perimeter =
Triangles
Perimeter
1 2 3 4 5 6
How does the perimeter change as the number of triangles
changes?
Resources for Algebra •• B-38 •• Public Schools of North Carolina
Perimeter
1 2 3 4 5 6
How does the perimeter change as the number of 3-squares
changes?
If the length of each side of a square is one unit, what are the
perimeters of each of these figures?
perimeter = perimeter =
perimeter = perimeter =
3-Squares
Resources for Algebra •• B-39 •• Public Schools of North Carolina
Patterns in Area and Volume
If each edge of the first figure (cube) has a length of one unit, what is the suface area of the figures in
each set? What is the volume of of the figures in each set? Fill in the table accompanying each set of
figures.
1 2 3 4
L-Tower 1 2 3 7 12 n
Area
Volume
1 2 3
Mid-Tower 1 2 3 9 25 n
Area
Volume
Resources for Algebra •• B-40 •• Public Schools of North Carolina
2L-Tower 1 3 4 12 31 n
Area
Volume
1 2 3 4
1
2
3
4
Cut Block 4 5
Area
Volume
Cut Block 10 n
Area
Volume
Resources for Algebra •• B-41 •• Public Schools of North Carolina
Blocks 4 5
Area
Volume
Blocks 9 n
Area
Volume
1
5
Steps 1 3 4 12 31 n
Area
Volume
1
4
3
2
43
2
Resources for Algebra •• B-42 •• Public Schools of North Carolina
The Picture Tells the (Linear) Story
Use your calculator to investigate each family of equations.
Sketch each equation's graph on the axes provided.
Answer the questions for each family of equations.
I.
y = x y = x + 6 y = x - 4
♦ How are the lines the same?
♦ What is different about the lines?
♦ Where does each line cross the y-axis?
♦ What happens to the graph when a constant is added to y = x?
♦ Write an equation for a line similar to those above but crosses the y-axis at 5.
♦ Write an equation for a line similar to those above but crosses the y-axis at -2.
♦ How are the lines alike?
♦ How are the lines different?
y = x
II.
y = -x
Resources for Algebra •• B-43 •• Public Schools of North Carolina
The Picture Tells the (Linear) Story
III.
y = x y = 2x y = 5x
y = 12 x y =
13 x y =
14 x
♦ Describe the differences in the graphs.
♦ Which line appears the steepest?
♦ What makes the difference?
Resources for Algebra •• B-44 •• Public Schools of North Carolina
The Picture Tells the (Linear) Story
IV.
y = -x y = -2x y = -4x
♦ How are the lines different?
♦ Which line appears the steepest?
♦ What makes the difference?
V.♦ Where does each of the following cross the y-axis?
♦ Which line is steepest and why.
y = 2x + 7 _____________________
y = -x + 11 _____________________
y = 12 x - 8 _____________________
♦ Where does each of the following cross the y-axis?
♦ Which line is steepest and why.
y = x + 8 _____________________
y = 3x - 4 _____________________
y = 12 x + 3 _____________________
♦ Where does each of the following cross the y-axis?
♦ Which line is steepest and why.
y = -x + 8 _____________________
y = -2x + 5 _____________________
y = - 13 x _____________________
♦ If a linear equation can be written in the form y = mx + b, where m and b represent any real values,
explain the effect of m on the graph of the equation.
♦ Explain the effect of b on the graph.
Resources for Algebra •• B-45 •• Public Schools of North Carolina
Moving on the Graph
Name ___________________
Write an equation you think will satisfy each of the conditions below.
Test your hypothesis with a calculator.
1. What do you do to the equation y = x to make its graph steeper?
Write two examples of such equations.
2. What do you do to the equation y = x to make its graph flatter?
Write two examples of such equations.
3. What do you do to the equation y = x to make its graph move up on the y-axis?
Write two examples of such equations.
4. What do you do to the equation y = x to make its graph move down on the y-axis?
Write two examples of such equations.
5. What do you do to the equation y = x to make its graph go through the second and
fourth quadrants?
Write two examples of such equations.
Resources for Algebra •• B-46 •• Public Schools of North Carolina
Guess My Slope and Y-intercept for the TI-81/82
Here is a program that will draw a line and allow the student to guess the slope and y-intercept. The
calculator will then draw the line for the guessed slope and y-intercept. If the graphs match, the student
receives 5 points. If the line is incorrect, the opponent can then try to guess the correct slope and
y-intercept.
0 STO M DispGraph
0 STO B Pause
Grid On Lbl 0
"CX + D" STO Y1
Disp "SLOPE?"
IPart (8Rand - 3) STO P Input M
IPart (3Rand + 1) STO D Disp "Y INTERCEPT?"
P/D STO C Input B
IPart (8Rand - 3) STO D DrawF MX + B
-6 STO Xmin Pause
6 STO Xmax Disp "TRY AGAIN?"
-4 STO Ymin Input A
4 STO Ymax If A=1
1 STO Xscl Goto 0
1 STO Yscl DispHome
1. Begin the program. The calculator will display a graph, then pause. (The first fourteen lines
randomly generate a slope and y-intercept for an equation with range, -6 ≤ x ≤ 6 and -4 ≤ y ≤ 4). Press
ENTER when you are ready to enter the slope and y-intercept. When the calculator asks for slope, type
in the slope and ENTER. When asked for the y-intercept, type in the y-intercept and ENTER. The
calculator will now graph the line you have described.
2. Check to see whether the new equation is the same line or not. ENTER. The calculator will ask,
"Try again?" If your line is not correct then pass the calculator to your opponent to try again.
3. To try again, your opponent types a 1 and ENTER. Then type in another slope and y-intercept.
4. If you have the correct line and do not want to try again, just type any number other than 1 for no.
5. You can show your students how to reprogram the calculator so that the steps will continue and allow
you to play the game over and over.
At the beginning of the program insert the two lines:
LBL 1
CLRHome
At the end of the program insert:
Disp"ANOTHER LINE?"
INPUT N
IF N=1
GOTO 1
The calculator will ask, "Another line?" You now type in 1 for yes, you want to play again. Type any
other number for no.
Resources for Algebra •• B-47 •• Public Schools of North Carolina
AAAA
BBBB CCCC
DDDD
Resources for Algebra •• B-48 •• Public Schools of North Carolina
Making Sense of Slope
1. Viper Video charges a membership fee per year in addition to the rental cost per tape.
The graph represents the annual cost as it varies with the number of tapes rented.
a) Calculate the slope. Explain what the slope represents in terms of number of tapes rented
and cost.
b) What does the y-intercept represent in this application?
30 60 90 120
100
200
300
400
Number of Tapes Rented
Tot
al C
ost
Annual Cost ofRenting Tapes
Tapes
Cost
0
7
30
82
60
157
90
232
120
307
Resources for Algebra •• B-49 •• Public Schools of North Carolina
2. A skydiver, during a jump, falls at a constant rate after the first ten seconds. The graph below
shows the altitude of the skydiver after x seconds.
a) Graph the data.
b) Calculate the slope. What is the meaning of the slope in terms of years and current value?
c) What is the meaning of the y-intercept?
d) Write an equation to describe the data.
0 31 2 4 5
15000 12400 9800 7200 4600 2000Truck Value
Years
3. The data below represent the value of a delivery truck as it depreciates over a period of 5 years.
a) Calculate the slope of the line after the first 10 seconds after point B). Explain the meaning of
the slope in terms of meters and seconds.
b) What is the meaning of the y-intercept in this application?
c) What is the meaning of the x-intercept?
d) Why might there be a steeper slope from point A to point B?
1000
2000
3000
4000
10 20 30 40 50
A
B
Seconds
Met
ers
Altitude over Time
0 3010 20 40 50
4000 3000 2500 2000 1500 1000
Seconds
Meters
Resources for Algebra •• B-50 •• Public Schools of North Carolina
4. The data below represent the distance traveled by a boat every 10 minutes.
a) Graph the data.
b) Calculate the slope. Describe the slope in terms of distance and minutes. Now, describe the
slope in terms of miles and hours.
c) Write the equation describing the data in minutes. Write an equation in hours.
d) What would be the distance traveled after 1.5 hours?
5. Write an application for the equation: y = 3.5x + 4
a) Complete a table and graph.
b) Interpret the meaning of the slope.
c) Interpret the y-intercept.
3010 20 40 50
4 8 12 16 20
Minutes
Distance
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