Georgia Common Core GPS Coordinate Algebra Supplement: Unit 2s3.amazonaws.com/.../Unit_2_Student_Workpack_Coordinate_Alg.pdf · Georgia Common Core GPS Coordinate Algebra Supplement:

Georgia Common Core GPS Coordinate Algebra Supplement:Unit 2

by David Rennie

Adapted from the Georgia Department of Education

Frameworks

Georgia Common Core GPS Coordinate Algebra Supplement: Unit 2 by David Rennie (Adapted from the

Georgia Department of Education Frameworks) is licensed under a Creative Commons Attribution-

NonCommercial 3.0 United States License.

All content provided in this work are originally developed by the Georgia Department of Education with all rights

reserved as of June 2012. All work must be reproduced in its entirety with the exception of “Warm-up” sections which are

attributed to David Rennie. Additional copyright attributes cited where appropriate.

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Common Core Algebra: Unit 2Jaden’s Phone Plan Mathematical Goals

• Create one-variable linear equations and inequalities from contextual situations.

• Solve and interpret the solution to multi-step linear equations and inequalities in context.

Common Core State Standards • MCC9 12.A.REI.1:‐ Explain each step in solving a simple equation as following from the equality of numbers

asserted at the previous step, starting from the assumption that the original equation has a solution. Construct a

viable argument to justify a solution method.

• MCC9 12.A.REI.3:‐ Solve linear equations and inequalities in one variable, including equations with coefficients

represented by letters.

Standards for Mathematical Practice • (1) Make sense of problems and persevere in solving them.

• (2) Reason abstractly and quantitatively.

• (3) Construct viable arguments and critique the reasoning of others.

• (4) Model with mathematics.

Introduction In this task, students will solve a series of linear equations and inequality word problems to help Jaden choose a cell

phone plan. In order to help Jaden, students must explain in detail each step of the problem and justify the answer.

Materials • Paper

• Pencil

All material contained in this pack are adapted from the Georgia Department of Education CCGPS Coordinate Algebra Framework. All copyrights are reserved to the

GADOE unless otherwise noted on the information page of each section. PAGE: 2 of 39

Common Core Algebra: Unit 2Jaden’s Phone Plan Warm-up

A phone company charges 25 cents for each picture message received by an individual caller while text messages cost only 2 cents per message received.

For each of the following situations, find the total cost each caller must pay given the number of

messages received. For the last problem, find the number of text messages received.

1. Sarah got 2 picture messages and 100 text messages.

2. Kevin received 25 picture messages and 17 text messages.

3. Brianna paid $7.50 in message charges. She knows she received 12 picture messages. How many text messages

were received by Brianna?

The Task (Part 1)

Jaden has a prepaid phone plan (Plan A) that charges 15 cents for each text sent and 10 cents per minute for calls.

1. If Jaden uses only text, write an equation for the cost C of sending t texts.

(a) How much will it cost Jaden to send 15 texts? Justify your answer.

(b) If Jaden has $6, how many texts can he send? Justify your answer.



Common Core Algebra: Unit 22. If Jaden only uses the talking features of his plan, write an equation for the cost C of talking m minutes.

(a) How much will it cost Jaden to talk for 15 minutes? Justify your answer.

(b) If Jaden has $6, how many minutes can he talk? Justify your answer.

3. If Jaden uses both talk and text, write an equation for the cost C of sending t texts and talking m minutes.

(a) How much will it cost Jaden to send 7 texts and talk for 12 minutes? Justify your answer.

(b) If Jaden wants to send 21 texts and only has $6, how many minutes can he talk?

(c) Will Jaden use all of his money in part (b)? If not, will how much money will he have left? Justify your answer.



Common Core Algebra: Unit 2The Task (Part 2)

Jaden discovers another prepaid phone plan (Plan B) that charges a flat fee of $15 per month, then $.05 per text sent or minute used.

1. Write an equation for the cost of Plan B.

Assume that in an average month, Jaden sends 200 texts and talks for 100 minutes.

2. Which plan will cost Jaden the least amount of money (Plan A from Part 1 or Plan B from Part 2)? Justify your

answer.



Common Core Algebra: Unit 2Solving Systems of Equations Algebraically Mathematical Goals

• Model and write an equation in one variable and solve a problem in context.

• Create one-variable linear equations and inequalities from contextual situations.

• Represent constraints with inequalities.

• Solve word problems where quantities are given in different units that must be converted to understand the

problem.

Common Core State Standards • MCC9 12.A.REI.5:‐ Prove that, given a system of two equations in two variables, replacing one equation by the

sum of that equation and a multiple of the other produces a system with the same solutions.

• MCC9 12.A.REI.6:‐ Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on

pairs of linear equations in two variables.



• (3) Construct viable arguments and critique the reasoning of others.


Introduction In this task, students justify the solution to a system of equations by both graphing and substituting values into the system.

Students will then show that multiplying one or both equations in a system of equations by a constant creates a new

system with the same solutions as the original. This task will lead into using the elimination method for solving a system

of equations algebraically.

Materials • Ruler

• Calculator

• Notebook paper

• Pencil



Common Core Algebra: Unit 2Solving Systems of Equations Algebraically Warm-up

You are given the following system of two equations:

x+2 y=163 x – 4 y=−2

1. One common practice in mathematics when working with a system of equations is to label

the equations. Normally this is done by writing the label in parentheses to the left of the

equation. An example might look like the example to the right where the equation is the first line

is called Equation A and the equation in the second line is called Equation B. Take a moment to

label the equations given to you in this warm-up.

Does it matter which equation is labeled equation A and which one is labeled equation B?

2. What are some ways to show that the coordinate (6,5) is a solution to the system of equations given above?

The Task (Part 1)1. Using graph paper, prove that (6, 5) is a solution to the system by graphing both equations in the system on the same

grid.

2. Using algebraic techniques, prove that (6, 5) is a solution to the system by substituting the coordinate values in

for both equations.



Example 1: Linear Equations Labeled

(eq A):x+7=9(eq B): 2 x+14=18

Common Core Algebra: Unit 23. Multiply both sides of the equation x+2 y=16 by the constant 7 . The initial setup is shown for you. Be

sure to show all your work.

7∗( x+2 y)=7∗16

New Equation:_______________________

(a) Does the new equation still have a solution of (6, 5) ? Justify your answer.

(b) Why do you think the solution to the equation (did/did not) changed when you multiplied by the 7 ?

4. Multiply the equation x+2 y=16 by three other numbers. Recording the resulting equations.

(a) ___________________________

(b) ___________________________

(c) ___________________________

5. For each of the equations found in problem (6), is the coordinate (6,5) still a solution? Justify your answer.

6. Multiply the equation 3 x−4 y=−2 by 7 and record the equation. Prove that (6,5) is a solution to the

resulting equation you recorded.



Common Core Algebra: Unit 27. Multiply the equation 3 x – 4 y=−2 by three different numbers and record the resulting equations.

(a) ___________________________

(b) ___________________________

(c) ___________________________

8. Is the coordinate (6,5) a solution to the equations found in problem (9)? Justify your answer.

9. Summarize any finds/new learnings made during this activity so far.

Closing1. What is the solution to a system of equations and how can you prove it is the solution?

2. Does the solution change when you multiply one of the equations by a constant?

3. Does the value of the constant you multiply by matter?

4. Does it matter which equation you multiply by the constant?



Common Core Algebra: Unit 2Solving Systems of Equations Algebraically The Task (Part 2)

Consider the following system of equations:5 x+6 y=94 x+3 y=0

1. Show by substituting in the values that (−3,4) is a solution to the system of equations.

2. Multiply 4 x+3 y=0 by −5 . Then add your answer to 5 x+6 y=9 . Record your answer and label as a

new equation. Show your work below.

SETUP:−5∗(4 x+3 y)=(0)∗−5⇒ (ANSWER)

+ 5 x + 6 y = 9

(New Equation)

3. Is (−3,4) still a solution to the new equation in part (2)? Justify your answer.



Common Core Algebra: Unit 24. Using the same setup and steps from part (2), Multiply the equation 4 x+3 y=0 by −2 . Then add your

answer to 5 x+6 y=9 .

(a) What happened to the y variable in this new equation?

(b) Solve the new equation for the variable x .

(c) What is the value of x that solves this equation?

(d) Does the value of x found in part (4c) agree with the value you already new to be a solution?

5. How could you use the value of x from part (4c) to find a value for y from one of the original equations from

the system of equations?



Common Core Algebra: Unit 2The method you just used in problems (4) and (5) is called The Elimination Method

for solving a system of equations. When using the Elimination Method, one of the original variables is eliminated from the system by adding the two equations together (sometimes after multiplying one or both of the equations by a constant on both sides).

Use the Elimination Method to solve the following system of equations:

6. −3 x+2 y=−65 x – 2 y=18 7. −5 x+7 y=11

5 x+3y=19



Common Core Algebra: Unit 2Solving Systems of Equations Algebraically The Task (Part 3)

When using the Elimination Method, one of the original variables is eliminated from the system by adding the two equations together. Sometimes it is necessary to multiply one or both of the original equations by a constant. The equations are then added together and one of the variables is eliminated.

Use the Elimination Method to solve the following system of equations:

(Equation 1) 4 x+3 y = 14(Equation 2) −2 x+ y = 8

1. Your choice of which variable to eliminate will change the steps you choose to take. First focus on eliminating the

x variable.

(a) The coefficients of x are 4 and – 2 . If you want to eliminate the x variable, you should

multiply Equation 2 by what constant?

(b) Multiply Equation 2 by the constant from part (1a). Add the resulting new equation to Equation 1. Record

your answer after showing all of your steps.

(c) What happened to the x variable?

(d) Solve the resulting equation from (1b) for any variable that is remaining. Show all of your work and record the

answer when done.



Common Core Algebra: Unit 2(e) Substitute the value from (1d) into Equation 1 and solve for any remaining variable. Show all of your work and

record your answer.

(f) Using your answers from (1d) and (1e) you should have a solution to the system of equations. What is the

solution to the system of equations?

2. Given the solution you obtained in (1f), do you think you would have obtained the same answer if the y variable

had been eliminated? Justify your answer.



Common Core Algebra: Unit 23. Consider focusing on Equation 1 and Equation2 again but paying attention to the y variable this time.

(a) The coefficients of y are 3 and 1 . If you want to eliminate the y term, you should multiply

Equation 2 by what constant?

(b) Multiply Equation 2 by the constant from (3a). Then add your answer equation to Equation 1. Recording your

answer after showing all of your work.

(c) What happened to the y variable?

(d) Solve the resulting equation from (3b) for any variable that is remaining. Show all of your work and record the

answer when done.

(e) Substitute the value from (1d) into Equation 1 and solve for any remaining variable. Show all of your work and

record your answer.

(f) Using your answers from (3d) and (3e) you should have a solution to the system of equations. What is the

solution to the system of equations?



Common Core Algebra: Unit 2Use your findings from problem 1 and problem 3 to answer the following questions in sentence

form.

4. Do you need to eliminate both variables to solve a system of equations?

5. What are some things you should consider when deciding which variable to eliminate? Is there a wrong variable to

eliminate?

6. Verify that the solution you found in Problem 1 and Problem 3 is a solution to both Equation 1 and Equation 2 using

substitution. Be sure to show all your work.

ClosingUse your findings from problem 1 and problem 3 to answer the following questions in sentence

form.

1. Is the ordered pair solution the same for either variable that is eliminated? Justify your answer.

2. Would you need to eliminate both variables to solve the problem? Justify your answer.

3. What are some things you should consider when deciding which variable to eliminate? Is there a wrong variable to

eliminate?

4. How do you decide what constant to multiply by in order to make the chosen variable eliminate?



Common Core Algebra: Unit 2Solving Systems of Equations Algebraically Homework

1. 3 x+2 y = 6−6 x – 3 y =−6 2. −6 x+ 5 y = 4

7 x – 10 y =−8 3. 5 x+ 6 y =−162 x+10 y = 5



Common Core Algebra: Unit 2Summer Job Mathematical Goals

• Model and write an inequality in two variables and solve a problem in context.

• Create two-variable linear equations and inequalities from contextual situations.

• Solve word problems involving inequalities.


Common Core State Standards • MCC9 12.A.REI.12:‐ Graph the solutions to a linear inequality in two variables as a half plane (excluding the‐

boundary in the case of a strict inequality), and graph the solution set to a system of linear inequalities in two

variables as the intersection of the corresponding half planes. ‐




• (5) Use appropriate tools strategically.

• (6) Attend to precision.

Introduction In this task, students will write a model for an inequality from the context of a word problem using real life situations. The

students will then graph the inequality in two variables and analyze the solution. Students will reason quantitatively and

use units to solve problems.

Materials • Graph paper

• Notebook paper

• Ruler

• Pencil

• Colored Pencils



Common Core Algebra: Unit 2Summer Job Warm-up

In order to raise money, you are planning to work during the summer babysitting and cleaning houses. You earn $10 per hour while babysitting and $20 per hour while cleaning houses. You need to earn at least $1000 during the summer.

1. Write an expression to represent the amount of money earned while babysitting. Be sure to choose a variable to

represent the number of hours spent babysitting.

2. Write an expression to represent the amount of money earned while cleaning houses.

3. Does the amount of money you earned over the summer need to be exactly $1000? Justify your answer.

The Task (Part 1)1. Suppose all of the information from the Warm-up is still valid. Write a mathematical formula that relates the total

amount of money earned over the summer ( T ) to the number of hours spent cleaning ( c ) and the number of

hours spent babysitting ( b ).

2. Write a mathematical relationship between the total money earned over the summer and the goal of $1000.



Common Core Algebra: Unit 23. Complete the following table based on your formula from part(2).

Hours Spent Babysitting

Hours Spent Cleaning

Total Money Earned

0 $1000

0 $1000

50 $1000

70 20

$1000

$1000

$1100

4. Is there more than one way to earn $1100? Justify your answer.

5. Consider making a graph that would model this situation provided in the table. Use the provided graph as a guide.



Common Core Algebra: Unit 26. Use the graph to answer the following questions

(a) Why does the graph only fall in the 1st Quadrant?

(b) Is it acceptable to earn exactly $1000?

(c) What are some possible combinations of outcomes that equal exactly $1000?

(d) Where do all of the outcomes that total $1000 lie on the graph?

(e) Is it acceptable to earn more than $1000?

(f) What are some possible combinations of outcomes that total more than $1000?

(g) Where do all of these outcomes fall on the graph?



Common Core Algebra: Unit 27. Use the graph to answer the following

(a) Is it acceptable to work 10 hours babysitting and 10 hours cleaning houses? Why or why not?

(b) Where does the combination of 10 hours babysitting and 10 hours cleaning houses fall on the graph?

(c) Are combinations that fall in this area a solution to the mathematical model? Why or why not?

8. How would the model change if you had to earn more than $1000?

(a) Write a new model to represent needing to earn more than $1000.

(b) How would this change the graph of the model?

(c) Would the line still be part of the solution?

(d) How would you change the line to show this?



Common Core Algebra: Unit 29. Graph the new model from part (8)



Common Core Algebra: Unit 2Summer Job The Task (Part 2)

You plan to use part of the money you earned from your summer job to buy jeans and shirts for school. Jeans cost $40 per pair and shirts are $20 each. You want to spend less than $400 of your money on these items.

1. Write a mathematical model representing the amount of money spent on jeans and shirts. Be sure to clearly

identify the variables used in this model.

2. Graph the model defined above. Place the number of jeans on the x-axis and the number of shirts on the y-axis.



Common Core Algebra: Unit 23. Use the graph to answer the following questions

(a) Why does the graph only fall in the 1st Quadrant?

(b) Is it acceptable to spend less than $400?

(c) What are some possible combinations of outcomes that spend less than $400?

(d) Where do all of the combinations that spend less than $400 fall on the graph?

(e) Is it acceptable to spend exactly $400?

(f) List at least three combinations of shirts and jeans that cost exactly $400.

(g) Where do all of the combinations that spend exactly $400 fall on the graph?

(h) Is it acceptable to spend more than $400?

(i) List out at least three combination of shirts and jeans that cost more than $400.

(j) Where do all of the combinations that spend more than $400 fall on the graph?



Common Core Algebra: Unit 2Summer Job ClosingSummarize your knowledge of graphing inequalities in two variables by answering the following

questions in sentence form:

1. Explain the difference between a solid line and a broken line when graphing inequalities.

(a) How can you determine from the model whether the line will be solid or broken?

(b) How can you look at the graph and know if the line is part of the solution?

2. How do you determine which area of the graph of an inequality to shade?

(a) What is special about the shaded area of an inequality?

(b) What is special about the area that is not shaded?



Common Core Algebra: Unit 2Graphing InequalitiesMathematical Goals





Common Core State Standards• MCC9 12.A.REI.12:‐ Graph the solutions to a linear inequality in two variables as a half plane (excluding the‐


variables as the intersection of the corresponding half planes.‐

Standards for Mathematical Practice• (1) Make sense of problems and persevere in solving them.





IntroductionIn this task, students will graph two separate inequalities in two variables and analyze the graph for solutions to each. The

students will then graph the two inequalities in two variables on the same coordinate system to show that the solution to

both inequalities is the area where the graphs intersect.

Materials• Colored pencils

• Pencil

• Calculator

• Paper

• Ruler



Common Core Algebra: Unit 2Graphing InequalitiesWarm-up

1. Graph the inequality y>−12

x+5 . List out at least

three solutions to this inequality.

2. Graph the inequality y<x+2 . List out at least

three solutions to this inequality.

The Task1. Look at the two graphs from the Warm-up.

(a) There are solutions that work for both inequalities. List out three examples of these solutions.

(b) There are solutions that work for 1 inequality but not the other? Give 3 examples and show which inequality

each example works for.



Common Core Algebra: Unit 22. On grid paper, graph both inequalities. Use a different color to shade each inequality.

(a) Look at the region that is shaded in both colors. What does this region represent?

(b) Look at the regions that are shaded in only 1 color. What do these regions represent?

(c) Look at the region that is not shaded. What does this region represent?

3. Graph the following system on the same coordinate grid. Use a different color for each. x+y≥3y≤−x+5

(a) Give three coordinates that are solutions to the system.

(b) Give three coordinates that are not solutions to the system.

(c) Is a coordinate on either line a solution to the system? Justify your answer.

(d) How would you change the inequality x+ y≥3 so that it would shade below the line?

(e) How would you change the inequality y≤−x+5 so that it would shade above the line?



Common Core Algebra: Unit 24. Graph the new inequalities from part (3f) and (3e) on the same coordinate grid (creating a new system of

inequalities). Use blue to shade the solution set for one inequality and red for the other inequality.

(a) What do the coordinates in blue represent?

(b) What do the coordinates in red represent?

(c) Why do the colors not overlap this time?

Homework Graph each of the following systems on the same coordinate grid and give 3 solutions for each

system.

1. 2 x+3 y<6x+5 y>5

2.y≥ 1

2x –1

y≤− 14

x+6

3.3 x – 4 y>5

y>34

x+1



Common Core Algebra: Unit 2Family OutingMathematical Goals





Common Core State Standards• MCC9 12.A.REI.1:‐ Explain each step in solving a simple equation as following from the equality of numbers

asserted at the previous step, starting from the assumption that the original equation has a solution. Construct a

viable argument to justify a solution method.

• MCC9 12.A.REI.3:‐ Solve linear equations and inequalities in one variable, including equations with coefficients

represented by letters.

• MCC9 12.A.REI.5:‐ Prove that, given a system of two equations in two variables, replacing one equation by the

sum of that equation and a multiple of the other produces a system with the same solutions.

• MCC9 12.A.REI.6:‐ Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on

pairs of linear equations in two variables.

• MCC9 12.A.REI.12:‐ Graph the solutions to a linear inequality in two variables as a half plane (excluding the‐



• MCC9 12.A.REI.12:‐ Graph the solutions to a linear inequality in two variables as a half plane (excluding the‐



Standards for Mathematical Practice• (1) Make sense of problems and persevere in solving them.







Common Core Algebra: Unit 2IntroductionIn this task, students will write a model for an inequality from the context of a word problem using real life situations. The

students will then graph the inequality in two variables and analyze the solution. Students will reason quantitatively and

use units to solve problems.

Materials• Pencil

• Colored Pencils

• Ruler

• Calculator



Common Core Algebra: Unit 2Family OutingWarm-up

You and your family are planning to rent a van for a 1 day trip to Family Fun Amusement Park in Friendly Town. For the van your family wants, the Wheels and Deals Car Rental Agency charges $25 per day plus 50 cents per mile to rent the van. The Cars R Us Rental Agency charges $40 per day plus 25 cents per mile to rent the same type van.

List out any key information that is important for this scenario.

The Task (Part 1)1. Write a mathematical model to represent the cost of renting a van from the Wheels and Deals Agency for 1 day.

(a) Do the units matter for this equation?

(b) Use the equation to determine the cost for renting the van from this agency for 1 day and driving 40 miles.



Common Core Algebra: Unit 22. Write a mathematical model to represent the cost of renting from the Cars R Us Agency for 1 day.

(a) Do the units for this equation match the units for the equation in problem 1?

(b) Does this matter when comparing the 2 equations?

(c) Use the equation from section (2) to determine the cost for renting the van from Cars R Us for 1 day and

driving 40 miles.

3. Graph the 2 models from section(1) and section (2) on the same coordinate system. Be sure to extend the lines until

they intersect.

(a) Where do the 2 lines intersect?

(b) What does the point of intersection represent?

(c) When is it cheaper to rent from Wheels and Deals?

(d) When is it cheaper to rent from Cars R Us?



Common Core Algebra: Unit 24. Friendly Town is approximately 80 miles from your home town. Which agency should you choose to rent a vehicle?

Justify your answer.



Common Core Algebra: Unit 2Family OutingThe Task (Part 2)

When you leave the car rental agency, your father goes to the Fill ‘er Up Convenience Store for gas. The gas hand indicates the van is on empty, so your father plans to fill the tank. Gas at the station is $3.49 per gallon.

1. If your father spends $78 on gas, approximately how many gallons did he purchase? Be sure to show all work to

justify your answer.

While in the store, your father purchases drinks for the six people in your van. Part of your family wants coffee and the rest want a soda.

2. Coffee in the store costs $.49 per cup and sodas are $1.29 each. The cost of the drinks before tax was $6.14.

(a) Write a mathematical model that represents the total number of cups of coffee and sodas.

(b) Write a mathematical model that represents the cost of the coffee and soda.

(c) Solve the system of equations using the elimination method.



Common Core Algebra: Unit 2When you arrive in Friendly Town at the Family Fun Amusement Park, the 6 people in your family pair up to enter the park. You and your brother decide to enter and ride together. The cost to enter the park is $10, with each ride costing $2.

3. You bring $55 to the park. You must pay to enter the park and you budget an additional $10 for food. Write and

solve an inequality to determine the maximum number of rides you can ride. Explain your answer.

4. Your brother brings $70 to the park and budgets $12 for food. How many more rides can he ride than you? Explain

your answer.

Inside the park, there are 2 vendors that sell popcorn and cotton candy. Jiffy Snacks sells both for $2.50 per bag. Quick Eats has cotton candy for $4 per bag and popcorn for $2 per bag.

5. If you use the $10 you budgeted for food, write an inequality to model the possible combinations of popcorn and

cotton candy you can purchase from Jiffy Snacks.



Common Core Algebra: Unit 26. Write an inequality to model the possible combinations of popcorn and cotton candy you can purchase from Quick

Eats.

7. Graph a system of inequalities from sections (5) and (6). Give two combinations that work for both vendors.

8. Assuming you purchase at least one bag of each snack, what is the maximum number of bags of cotton candy and

popcorn that work for both equations?



Common Core Algebra: Unit 2Family OutingThe Task (Part 3)Assume that the information from The Task (Part 2) is still true for the remainder of Part 3.

When you leave the park, your father notices that you have used 34 of the

tank of gas you purchased before you left.

1. Do you have enough gas to get home? Justify your answer.

2. Your father wants to purchase enough gas to get home, but not leave extra in the tank when the van is returned to

the rental agency. Approximately how many more gallons should he purchase? Justify your answer.



Documents

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