12
Algebra 2 3 Linear Systems and Matrices Practice Problems 3.1 Solve Linear Systems by Graphing Graph the linear system and estimate the solution. Then check the solution algebraically. 1. { = −3 + 2 = 2 − 3 2. { = − + 3 − − 3 = −1 3. { = 2 − 10 − 4 = 5 4. { = −3 − 2 5 + 2 = −2 5. { − 7 = 6 −3 + 21 = −18 6. { 5 − 4 = 3 3 + 2 = 15 Graph and solve the system. Then classify the system as consistent and independent, consistent and dependent, or inconsistent. 7. { = −1 3 + = 5 8. { = 3 + 2 = 3 − 2 9. { −20 + 12 = −24 5 − 3 = 6 10. { 3 + 7 = 6 2 + 9 = 4 11. { 8 + 9 = 15 5 − 2 = 17 12. { 3 − 2 = −15 2 3 = −5 Graph the system and estimate the solution(s). Then check the solution(s) algebraically. 13. { = | + 2| = Problem Solving 14. You worked 14 hours last week and earned a total of $96 before taxes. Your job as a lifeguard pays $8 per hour, and your job as a cashier pays $6 per hour. How many hours did you work at each job? 15. A gym offers two options for membership plans. Option A includes an initiation fee of $121 and costs $1 per day. Option B has no initiation fee but costs $12 per day. After how many days will the total costs of the gym membership plans be equal? How does your answer change if the daily cost of Option B increases? Explain. Mixed Review 16. (2-08) Graph >− 1 3 +2 17. (2-04) Write the equation of the line that passes through (-2, 1) and (3, 5). 18. (1-07) Solve |2 + 5| = 12 19. (1-04) Solve for y. 3 − 2 = 8 20. (1-03) Solve 8 + 1 = 3 − 14

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Page 1: Algebra 2 3 Linear Systems and Matrices Practice Problems ...rwright/algebra2/homework...Algebra 2 3 Linear Systems and Matrices Practice Problems 3.1 Solve Linear Systems by Graphing

Algebra 2 3 Linear Systems and Matrices Practice Problems

3.1 Solve Linear Systems by Graphing Graph the linear system and estimate the solution. Then check the solution algebraically.

1. {𝑦 = −3𝑥 + 2𝑦 = 2𝑥 − 3

2. {𝑦 = −𝑥 + 3

−𝑥 − 3𝑦 = −1

3. {𝑦 = 2𝑥 − 10𝑥 − 4𝑦 = 5

4. {𝑦 = −3𝑥 − 25𝑥 + 2𝑦 = −2

5. {𝑥 − 7𝑦 = 6

−3𝑥 + 21𝑦 = −18

6. {5𝑥 − 4𝑦 = 33𝑥 + 2𝑦 = 15

Graph and solve the system. Then classify the system as consistent and independent, consistent and dependent, or inconsistent.

7. {𝑦 = −13𝑥 + 𝑦 = 5

8. {𝑦 = 3𝑥 + 2𝑦 = 3𝑥 − 2

9. {−20𝑥 + 12𝑦 = −24

5𝑥 − 3𝑦 = 6

10. {3𝑥 + 7𝑦 = 62𝑥 + 9𝑦 = 4

11. {8𝑥 + 9𝑦 = 155𝑥 − 2𝑦 = 17

12. {3𝑥 − 2𝑦 = −15

𝑥 −2

3𝑦 = −5

Graph the system and estimate the solution(s). Then check the solution(s) algebraically.

13. {𝑦 = |𝑥 + 2|

𝑦 = 𝑥

Problem Solving 14. You worked 14 hours last week and earned a total of $96 before taxes. Your job as a lifeguard pays $8 per

hour, and your job as a cashier pays $6 per hour. How many hours did you work at each job?

15. A gym offers two options for membership plans. Option A includes an initiation fee of $121 and costs $1 per

day. Option B has no initiation fee but costs $12 per day. After how many days will the total costs of the

gym membership plans be equal? How does your answer change if the daily cost of Option B increases?

Explain.

Mixed Review

16. (2-08) Graph 𝑦 > −1

3𝑥 + 2

17. (2-04) Write the equation of the line that passes through (-2, 1) and (3, 5).

18. (1-07) Solve |2𝑥 + 5| = 12

19. (1-04) Solve for y. 3𝑥 − 2𝑦 = 8

20. (1-03) Solve 8𝑥 + 1 = 3𝑥 − 14

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.2 Solve Linear Systems Algebraically Solve the system using the substitution method.

1. {2𝑥 + 5𝑦 = 7

𝑥 + 4𝑦 = 2 2. {

3𝑥 − 𝑦 = 26𝑥 + 3𝑦 = 14

3. {3𝑥 + 𝑦 = −1

2𝑥 + 3𝑦 = 18

Solve the system using the elimination method.

4. {2𝑥 + 6𝑦 = 17

2𝑥 − 10𝑦 = 9 5. {

5𝑥 − 3𝑦 = −32𝑥 + 6𝑦 = 0

6. {3𝑥 + 4𝑦 = 186𝑥 + 8𝑦 = 18

7. Describe and correct the error in the first step of solving the system.

{3𝑥 + 2𝑦 = 75𝑥 + 4𝑦 = 15

Solve the system using any algebraic method.

8. {4𝑥 − 10𝑦 = 18−2𝑥 + 5𝑦 = −9

9. {3𝑥 + 𝑦 = 15

−𝑥 + 2𝑦 = −19

10. {2𝑥 + 𝑦 = −1

−4𝑥 + 6𝑦 = 6

11. {

1

2𝑥 +

2

3𝑦 =

5

65

12𝑥 +

7

12𝑦 =

3

4

Use the elimination method to solve the system.

12. {7𝑦 + 18𝑥𝑦 = 30

13𝑦 − 18𝑥𝑦 = 90

Problem Solving 13. In one week, a music store sold 9 guitars for a total of $3611. Electric guitars sold for $479 each and

acoustic guitars sold for $339 each. How many of each type of guitar were sold?

14. An adult pass for a county fair costs $2 more than a children’s pass. When 378 adult and 214 children’s

passes were sold, the total revenue was $2384. Find the cost of an adult pass.

15. A nut wholesaler sells a mix of peanuts and cashews. The wholesaler charges $2.80 per pound for peanuts

and $5.30 per pound for cashews. The mix is to sell for $3.30 per pound. How many pounds of peanuts and

how many pounds of cashews should be used to make 100 pounds of the mix?

Mixed Review

16. (3-01) Solve by graphing: {3𝑥 + 𝑦 = 11𝑥 − 2𝑦 = −8

17. (3-01) Solve by graphing: {𝑥 − 2𝑦 = −23𝑥 + 𝑦 = −20

18. (2-02) Tell whether the lines are parallel, perpendicular, or neither:

Line 1: through (4, 5) and (9, -2)

Line 2: through (6, -6) and (-2, -1)

19. (1-07) Solve |𝑥 + 3| = 4

20. (1-03) Solve 6(2𝑎 − 3) = −30

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.3 Graph Systems of Linear Inequalities Graph the system of inequalities.

1. {−𝑥 + 𝑦 < −3−𝑥 + 𝑦 > 4

2. {4𝑥 − 4𝑦 ≥ −16−𝑥 + 2𝑦 ≥ −4

3. {𝑦 > |𝑥| − 4

3𝑦 < −2𝑥 + 9

4. {2𝑦 < −5𝑥 − 105𝑥 + 2𝑦 > −2

5. {𝑥 − 4𝑦 ≤ −10

𝑦 ≤ 3|𝑥 − 1|

6. {𝑥 < 6𝑦 > −1𝑦 < 𝑥

7. {

3𝑥 + 2𝑦 > −6−5𝑥 + 2𝑦 > −2

𝑦 < 5

8. {𝑥 ≥ 2

−3𝑥 + 𝑦 < −14𝑥 + 3𝑦 < 12

9. {

𝑦 ≥ 0𝑥 > 3

𝑥 + 𝑦 ≥ −2𝑦 < 4𝑥

10. {

𝑥 ≤ 10𝑥 ≥ −2

3𝑥 + 2𝑦 < 66𝑥 + 4𝑦 > −12

Write a system of linear inequalities for the shaded region.

11.

Problem Solving 12. The Junior-Senior Banquet Committee must consist of 5 to 8 representatives from the junior and senior

classes. The committee must include at least 2 juniors and at least 2 seniors. Let x be the number of juniors

and y be the number of seniors.

a. Writing a System Write a system of inequalities to describe the situation.

b. Graphing a System Graph the system you wrote in part (a).

c. Finding Solutions Give two possible solutions for the numbers of juniors and seniors on the prom

committee.

Mixed Review

13. (3-02) Solve {9𝑥 + 4𝑦 = −73𝑥 − 5𝑦 = −34

14. (3-02) Solve {𝑥 − 5𝑦 = 18

2𝑥 + 3𝑦 = 10

15. (1-06) Solve 𝑥 − 8 ≤ −5

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.4 Solve Systems of Linear Equations in Three Variables 1. Write a linear equation in three variables. What is the graph of such an equation?

Tell whether the given ordered triple is a solution of the system. 2. (6, 0, -3)

{𝑥 + 4𝑦 − 2𝑧 = 123𝑥 − 𝑦 + 4𝑧 = 6−𝑥 + 3𝑦 + 𝑧 = −9

Solve the system using the elimination method.

3. {

3𝑥 + 𝑦 + 𝑧 = 14−𝑥 + 2𝑦 − 3𝑧 = −9

5𝑥 − 𝑦 + 5𝑧 = 30 4. {

5𝑥 + 𝑦 − 𝑧 = 6𝑥 + 𝑦 + 𝑧 = 2

3𝑥 + 𝑦 = 4

Solve the system using the substitution method.

5. {

𝑥 + 𝑦 − 𝑧 = 43𝑥 + 2𝑦 + 4𝑧 = 17−𝑥 + 5𝑦 + 𝑧 = 8

6. {2𝑥 − 𝑦 + 𝑧 = −2

6𝑥 + 3𝑦 − 4𝑧 = 8−3𝑥 + 2𝑦 + 3𝑧 = −6

Describe and correct the error in the first step of solving the system.

{

𝟐𝒙 + 𝒚 − 𝟐𝒛 = 𝟐𝟑𝟑𝒙 + 𝟐𝒚 + 𝒛 = 𝟏𝟏

𝒙 − 𝒚 + 𝒛 = −𝟐

7. Solve the system using any algebraic method.

8. {𝑥 + 5𝑦 − 2𝑧 = −1−𝑥 − 2𝑦 + 𝑧 = 6

−2𝑥 − 7𝑦 + 3𝑧 = 7 9. {

2𝑥 − 𝑦 + 2𝑧 = −21𝑥 + 5𝑦 − 𝑧 = 25

−3𝑥 + 2𝑦 + 4𝑧 = 6 10. {

𝑥 + 𝑦 + 𝑧 = 33𝑥 − 4𝑦 + 2𝑧 = −28−𝑥 + 5𝑦 + 𝑧 = 23

Problem Solving 11. The juice bar at a health club receives a delivery of juice at the beginning of each month. Over a three

month period, the health club received 1200 gallons of orange juice, 900 gallons of pineapple juice, and

1000 gallons of grapefruit juice. The table shows the composition of each juice delivery. How many gallons

of juice did the health club receive in each delivery?

Mixed Review

12. (3-03) Graph {

𝑦 ≥ 𝑥𝑥 ≤ 4𝑦 ≥ 1

13. (3-03) Graph {𝑦 ≤ −

1

2𝑥 + 4

𝑦 > 𝑥 − 3

14. (3-02) Solve the system using any algebraic method: {3𝑥 − 𝑦 = −7

2𝑥 + 3𝑦 = 21

15. (2-02) Find the slope of the line passing through the given points. Then tell whether the line rises, falls, is

horizontal, or is vertical: (1, −4), (2, 6)

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.5 Perform Basic Matrix Operations 1. Copy and complete: The _?_ of a matrix with 3 rows and 4 columns are 3×4.

Perform the indicated operation, if possible. If not possible, state the reason.

2. [10 −85 −3

] − [12 −33 −4

] 3. [

1.2 5.30.1 4.46.2 0.7

] + [2.4 −0.66.1 3.18.1 −1.9

] 4. [7 −3

12 5−4 11

] − [9 2

−2 66 5

]

Perform the indicated operation.

5. −3 [2 0 −54 7 −3

]

6. 1.5 [−2 3.4 1.65.4 0 −3

]

7. −2.2 [6 3.1 4.5

−1 0 2.55.5 −1.8 6.4

]

Use matrices A, B, C, and D to evaluate the matrix expression.

𝑨 = [𝟓 −𝟒𝟑 −𝟏

] 𝑩 = [𝟏𝟖 −𝟏𝟐−𝟔 𝟎

] 𝑪 = [𝟏. 𝟖 −𝟏. 𝟓 𝟏𝟎. 𝟔

−𝟖. 𝟖 𝟑. 𝟒 𝟎] 𝑫 = [

𝟕. 𝟐 𝟎 −𝟓. 𝟒𝟐. 𝟏 −𝟏. 𝟗 𝟑. 𝟑

]

8. 𝐵 − 𝐴

9. 2

3𝐵

10. 𝐶 + 3𝐷

11. 0.5𝐶 − 𝐷

Solve the matrix equation for x and y.

12. [−2𝑥 6

1 −8] + 2 [

5 −1−7 6

] = [−9 4

−13 𝑦] 13. 4𝑥 [

−1 23 6

] = [8 −16

−24 3𝑦]

14. Prove one of the properties of matrix operations on page 188 for 2×2 matrices. (Hint: Apply any related

properties of real numbers from page 3.)

Problem Solving 15. A sporting goods store sells snowboards in several different styles and lengths. The matrices below show

the number of each type of snowboard sold in 2003 and 2004. Write a matrix giving the change in sales for

each type of snowboard from 2003 to 2004.

Mixed Review

16. (3-04) Solve {

2𝑥 − 𝑦 − 3𝑧 = 5𝑥 + 2𝑦 − 5𝑧 = −11

−𝑥 − 3𝑦 = 10 17. (3-04) Solve {

2𝑥 − 4𝑦 + 3𝑧 = 16𝑥 + 2𝑦 + 10𝑧 = 19−2𝑥 + 5𝑦 − 2𝑧 = 2

18. (3-03) Graph {𝑦 < 6𝑥 + 𝑦 > −2

19. (2-08) Check whether the ordered pairs are solutions of the inequality: 𝑥 + 2𝑦 ≤ −3; (0, 3), (-5, 1)

20. (2-07)

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.6 Multiply Matrices State whether the product AB is defined. If so, give the dimensions of AB.

1. 𝐴: 2 × 1, 𝐵: 2 × 2

2. If A is a 2×3 matrix and B is a 3×2 matrix, what are the dimensions of AB?

(A) 2×2 (B) 3×3 (C) 3×2 (D) 2×3

Find the product. If the product is not defined, state the reason.

3. [14

] [−2 1]

4. [9 −30 2

] [0 14 −2

]

5. [5 20 −41 6

] [3 7

−2 0] 6. [

1 3 02 12 −4

] [9 14 −3

−2 4]

Using the given matrices, evaluate the expression.

𝑨 = [𝟓 −𝟑

−𝟐 𝟒] , 𝑩 = [

𝟎 𝟏𝟒 −𝟐

] , 𝑪 = [−𝟔 𝟑𝟒 𝟏

] , 𝑫 = [𝟏 𝟑 𝟐

−𝟑 𝟏 𝟒𝟐 𝟏 −𝟐

] , 𝑬 = [−𝟑 𝟏 𝟒𝟕 𝟎 −𝟐𝟑 𝟒 −𝟏

]

7. −1

2𝐴𝐶

8. 𝐴𝐵 − 𝐵𝐴

9. (𝐷 + 𝐸)𝐷

10. 4𝐴𝐶 + 3𝐴𝐵

Problem Solving 11. Write an inventory matrix and a cost per item matrix. Then use matrix multiplication to write a total cost

matrix. A softball team needs to buy 12 bats, 45 balls, and 15 uniforms. Each bat costs $21, each ball costs

$4, and each uniform costs $30.

12. Matrix S gives the numbers of three types of cars sold in February by two car dealers, dealer A and dealer B.

Matrix P gives the profit for each type of car sold. Which matrix is defined, SP or PS? Find this matrix and

explain what its elements represent.

Mixed Review

13. (3-05) Simplify [3 −22 5

] + 2 [1 0

−4 0]

14. (3-02) Solve {3𝑥 − 5𝑦 = 112𝑥 + 5𝑦 = 24

15. (2-04) Write the equation of the line with slope: -3 and passes through (5, 2)

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.7 Evaluate Determinants and Apply Cramer’s Rule Evaluate the determinant of the matrix.

1. [2 −14 −5

]

2. [−4 31 −7

]

3. [10 −6−7 5

]

4. [9 −37 2

]

5. [−1 12 40 2 −53 0 1

]

6. [5 0 2

−3 9 −21 −4 0

]

7. [12 5 80 6 −81 10 4

]

8. [−2 6 08 15 34 −1 7

]

Find the area of the triangle with the given vertices. 9. 𝐴(4, 2), 𝐵(4, 8), 𝐶(8, 5) 10. 𝐴(−4, −4), 𝐵(−1, 2), 𝐶(2, −6) 11. 𝐴(−6, 1), 𝐵(−2, −6), 𝐶(0, 3)

Use Cramer’s rule to solve the linear system.

12. {3𝑥 + 5𝑦 = 3−𝑥 + 2𝑦 = 10

13. {5𝑥 + 𝑦 = −40

2𝑥 − 5𝑦 = 11

14. {

−𝑥 − 2𝑦 + 4𝑧 = −28𝑥 + 𝑦 + 2𝑧 = −11

2𝑥 + 𝑦 − 3𝑧 = 30

15. {5𝑥 − 𝑦 − 2𝑧 = −6𝑥 + 3𝑦 + 4𝑧 = 162𝑥 − 4𝑦 + 𝑧 = −15

16. {

3𝑥 − 𝑦 + 𝑧 = 25−𝑥 + 2𝑦 − 3𝑧 = −17

𝑥 + 𝑦 + 𝑧 = 21

Problem Solving 17. You are planning to turn a triangular region of your yard into a garden. The vertices of the triangle are

(0, 0), (5, 2), and (3, 6) where the coordinates are measured in feet. Find the area of the triangular region.

Mixed Review

18. (3-06) Simplify [2 −46 1

] [−3 01 7

]

19. (3-06) Simplify [1 03 −2

] [−5 102 0

]

20. (3-03) Graph {𝑥 + 𝑦 ≥ 3

4𝑥 + 𝑦 < 4

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.8 Use Inverse Matrices to Solve Linear Systems Find the inverse of the matrix.

1. [1 −5

−1 4]

2. [6 25 2

]

3. [−4 −64 7

]

4. [−24 60−6 30

]

Solve the matrix equation.

5. [1 14 5

] 𝑋 = [2 3

−1 6] 6. [

−1 06 4

] 𝑋 = [3 −14 5

] 7. [1 50 −2

] 𝑋 = [3 −1 06 8 4

]

Use an inverse matrix to solve the linear system.

8. {4𝑥 − 𝑦 = 10

−7𝑥 − 2𝑦 = −25

9. {3𝑥 − 2𝑦 = 56𝑥 − 5𝑦 = 14

10. {−2𝑥 − 9𝑦 = −24𝑥 + 16𝑦 = 8

11. {6𝑥 + 𝑦 = −2

−𝑥 + 3𝑦 = −25

Problem Solving 12. A pilot has 200 hours of flight time in single-engine airplanes and twin-engine airplanes. Renting a single-

engine airplane costs $60 per hour, and renting a twin-engine airplane costs $240 per hour. The pilot has

spent $21,000 on airplane rentals. Use an inverse matrix to find how many hours the pilot has flown each

type of airplane.

Mixed Review 13. (3-07) You are making a triangular sail for a sailboat. The vertices of the sail are (0, 2), (12, 2), and (12, 26)

where the coordinates are measured in feet. Find the area of the sail.

14. (3-07) Evaluate the determinant of [5 4

−2 −3]

15. (3-06) Evaluate 2 [1 −45 2

] [2 −30 1

]

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Algebra 2 3 Linear Systems and Matrices Practice Problems

3.Review Solve. Show some work.

1. {𝑥 − 5𝑦 = 10

𝑥 = 𝑦 + 2

2. {10𝑥 − 3𝑦 = 15

−10𝑥 + 5𝑦 = 21

3. {𝑥 + 7𝑦 − 2𝑧 = 10

𝑦 + 3𝑧 = 2𝑧 = 1

4. {𝑥 − 𝑦 + 𝑧 = 2

2𝑥 + 𝑦 = 4−𝑥 + 2𝑦 − 3𝑧 = −6

5. [3 𝑥

4𝑦 2] = [

3 1512 2

]

Perform the indicated operation.

6. [35

] − [5

10]

7. 10 [2 97 −3

]

8. 3 [2 31 −1

] + 2 [0 −2

−1 3]

9. [1 23 4

] [−4 −3−2 −1

]

10. [2 4] [3 −2

−1 0]

Evaluate the determinate of the matrix.

11. [10 −120 2

] 12. [

1 3 52 4 60 −1 −2

]

Use Cramer’s Rule to solve the linear system.

13. {2𝑥 − 3𝑦 = 6

𝑥 + 𝑦 = 2

14. Find the inverse of [2 −1

−3 4].

Use an inverse matrix to solve the linear system.

15. {2𝑥 − 𝑦 = 8

−3𝑥 + 4𝑦 = 1

16. For a fundraiser, a student sold a total of 20 tickets for $122. If child tickets are $5 and adult tickets are $7,

how many of each type of ticket did the student sell?

Graph the linear system and tell how many solutions it has. If there is exactly one solution, estimate the solution and check it algebraically.

17. {𝑦 = 2𝑥 − 3

𝑦 = −1

2𝑥 + 2

18. {𝑥 − 2𝑦 = −1

−3𝑥 + 𝑦 = −2

Graph the system of linear inequalities.

19. {𝑦 < 3

𝑥 + 2𝑦 > −2

20. {𝑦 ≤

2

3𝑥 + 4

𝑦 ≥2

3𝑥 − 1

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Algebra 2 3 Linear Systems and Matrices Practice Problems

Answers

3.1 1. (1, -1) 2. (4, -1) 3. (5, 0) 4. (-2, 4) 5. Infinitely many solutions 6. (3, 3) 7. (2, -1); consistent and independent 8. No solution; inconsistent 9. Infinitely many solutions;

consistent and dependent 10. (2, 0); consistent and independent 11. (3, -1); consistent and independent

12. Infinitely many solutions; consistent and dependent

13. No solution 14. Lifeguard: 6h, cashier: 8h 15. 11 days: the number of days will

decrease 16. 17. 4𝑥 − 5𝑦 = −13

18. −81

2, 3

1

2

19. 𝑦 =3

2𝑥 − 4

20. -3

3.2 1. (6, -1)

2. (4

3, 2)

3. (-3, 8)

4. (7,1

2)

5. (−1

2,

1

6)

6. No solution

7. Failed to multiply the constant by −2

8. Infinitely many solutions 9. (7, -6)

10. (−3

4,

1

2)

11. (-1, 2)

12. (−1

9, 6)

13. 5 acoustic, 4 electric

14. $4.75 15. 80 lbs. of peanuts, 20 lbs. of

cashews 16. (2, 5) 17. (-6, -2) 18. Neither 19. -7, 1 20. -1

3.3 1. No solution

2.

3. 4. No solution

5.

6.

7.

8.

9.

10.

11. {

𝑦 ≤ 3𝑦 ≥ −2𝑥 ≤ 4

𝑥 ≥ −3

12. {

𝑥 ≥ 2𝑦 ≥ 2

𝑥 + 𝑦 ≤ 8𝑥 + 𝑦 ≥ 5

; ;

Sample: 3Jr., 4Sr.; 4Jr., 4Sr. 13. (-3, 5) 14. (8, -2) 15. 𝑥 ≤ 3

Page 11: Algebra 2 3 Linear Systems and Matrices Practice Problems ...rwright/algebra2/homework...Algebra 2 3 Linear Systems and Matrices Practice Problems 3.1 Solve Linear Systems by Graphing

Algebra 2 3 Linear Systems and Matrices Practice Problems

3.4 1. Sample: 𝑥 + 𝑦 + 𝑧 = 4; plane 2. Yes 3. (1, 5, 6) 4. (𝑥, 4 − 3𝑥, 2𝑥 − 2) or

(1

2𝑧 + 1, −

3

2𝑧 + 1, 𝑧)

5. (3, 2, 1) 6. (0, 0, -2) 7. In the second equation, the

coefficient of y was not multiplied by 2.

8. (𝑦 − 11, 𝑦, 3𝑦 − 5) or

(1

3𝑧 −

28

3,1

3𝑧 +

5

3, 𝑧)

9. (-4, 5, -4) 10. (2, 6, -5) 11. 1st: 300 gal, 2nd: 750 gal, 3rd: 2050

gal

12.

13. 14. (0, 7) 15. 10; rises

3.5 1. dimensions

2. [−2 −52 1

]

3. [3.6 4.76.2 7.5

14.3 −1.2]

4. [−2 −514 −1

−10 6]

5. [−6 0 15

−12 −21 9]

6. [−3 5.1 2.48.1 0 −4.5

]

7. [−13.2 −6.82 −9.9

2.2 0 −5.5−12.1 3.96 −14.08

]

8. [13 −8−9 1

]

9. [12 −8−4 0

]

10. [23.4 −1.5 −5.6−2.5 −2.3 9.9

]

11. [−6.3 −0.75 10.7−6.5 3.6 −3.3

]

12. 𝑥 =19

2, 𝑦 = 4

13. 𝑥 = −2, 𝑦 = −16 14. Possible answer (for commutative

property of addition): 𝐴 =

[𝑎 𝑏𝑐 𝑑

] , 𝐵 = [𝑒 𝑓𝑔 ℎ

] ; 𝐴 + 𝐵 =

[𝑎 𝑏𝑐 𝑑

] + [𝑒 𝑓𝑔 ℎ

] =

[𝑎 + 𝑒 𝑏 + 𝑓𝑐 + 𝑔 𝑑 + ℎ

] = [𝑒 + 𝑎 𝑓 + 𝑏𝑔 + 𝑐 ℎ + 𝑑

] =

[𝑒 𝑓𝑔 ℎ

] + [𝑎 𝑏𝑐 𝑑

] = 𝐵 + 𝐴

15. [0 5 1 −1

−7 −1 −5 −21 −1 4 10

]

16. (2, -4, 1)

17. (−1

2, 1, 2)

18. 19. Not a solution; solution

20. 𝑦 = −3

2|𝑥 − 1| + 1

3.6 1. Not defined 2. A

3. [−2 1−8 4

]

4. [−12 15

8 −4]

5. [11 358 0

−9 7]

6. [21 −874 −50

]

7. [21 −6

−14 1]

8. [−10 7−8 10

]

9. [−2 4 05 15 8

−16 17 36]

10. [−204 81160 −38

]

11. 𝐵𝑎𝑡𝑠𝐵𝑎𝑙𝑙𝑠

𝑈𝑛𝑖𝑓𝑜𝑟𝑚𝑠[124515

],

𝐵𝑎𝑡 𝐵𝑎𝑙𝑙 𝑈𝑛𝑖𝑓𝑜𝑟𝑚

𝐶𝑜𝑠𝑡 [ 21 4 30];

𝐶𝑜𝑠𝑡𝐼𝑡𝑒𝑚 [ 882 ]

12. PS; [62,400 57,575], it shows the profit for all of the cars sold by each dealer.

13. [5 −2

−6 5]

14. (7, 2) 15. 𝑦 = −3𝑥 + 17

3.7 1. -6 2. 25 3. 8 4. 39 5. -206 6. -34 7. 1160 8. -480 9. 12

10. 21 11. 25 12. (-4, 3) 13. (-7, -5) 14. (6, -3, -7) 15. (0, 4, 1) 16. (8, 6, 7) 17. 12 ft2

18. [−10 −28−17 7

]

19. [−5 10

−19 30]

20.

Page 12: Algebra 2 3 Linear Systems and Matrices Practice Problems ...rwright/algebra2/homework...Algebra 2 3 Linear Systems and Matrices Practice Problems 3.1 Solve Linear Systems by Graphing

Algebra 2 3 Linear Systems and Matrices Practice Problems

3.8

1. [−4 −5−1 −1

]

2. [1 −1

−5

23 ]

3. [−

7

4−

3

2

1 1]

4. [−

1

12

1

6

−1

60

1

15

]

5. [11 9−9 −6

]

6. [−3 111

2−

1

4

]

7. [18 19 10−3 −4 −2

]

8. (3, 2) 9. (-1, -4) 10. (10, -2) 11. (1, -8) 12. Single: 150 h, twin: 50 h 13. 144 ft2 14. -7

15. [4 −14

20 −26]

3.Review 1. (0, −2)

2. (69

10, 18)

3. (19, −1, 1) 4. (1, 2, 3) 5. (15, 3)

6. [−2−5

]

7. [20 9070 −30

]

8. [6 51 3

]

9. [−8 −5

−20 −13]

10. [2 −4] 11. 40 12. 0

13. (12

5, −

2

5)

14. [

4

5

1

53

5

2

5

]

15. (33

5,

26

5)

16. 9 child, 11 adult 17. (2, 1);

18. (1, 1);

19.

20.