Unit 9 Matrices Practice Review

Essential Question:
How can I use matrices to solve real world problems?

​

Matrix Work Day!

• 9.1 Practice

• 9.2 Practice

• 9.3 Practice

📝What you need!

Poll

How do you currently feel about using matrices to solve problems?

• I feel great! I can help a friend.

• I need some help, please.

• I get it, but need more practice

Practice 9.1

Solving and Writing Systems of Equations

9.1 Notes KEY – Writing and Solving Systems of Equations.pdf - Google Drive

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Multiple Choice

Question 1 ON YOUR PAPER

What is the value of x in the solution for this system of equations?

Use the ⭐HINT⭐ if you need!

• x = 3

• x = 14

• x = -1

• Not here

Problem 2 HINT:

Use these equations to solve.

Multiple Select

Question 2 ON YOUR PAPER

Select BOTH the cost for a taco and cost of milk.

• t = $1.15

• m = $0.95

• t = $1.95

• m = $1.55

Problem 3 Hint:

Use these equations to solve.

Multiple Select

Question 3 ON YOUR PAPER

Find the length and width. Select BOTH answers.

TRY SUBSTITUTION!

• l = 33

• w = 11

• l = 22

• w = 44

Problem 4 Hint:

Use these equations to solve.

Multiple Select

Question 4 ON YOUR PAPER

Find BOTH the sundae and split costs.

TRY SUBSTITUTION!

• d = 36

• b = 28

• d = 20

• b = 24

Problem 5 Hint:

Use these equations to solve.

Multiple Select

Question 5 ON YOUR PAPER

Find the number of nickels and quarters.

• n = 25

• q = 10

• n = 20

• q = 15

Multiple Select

Question 6 ON YOUR PAPER

How many TWO-POINT questions? How many FOUR-POINT questions?

⭐HINT⭐

2x + 4y = 100

x + y = 40

• x = 30

• y = 10

• x = 15

• y = 25

Multiple Select

Question 7 ON YOUR PAPER

Select ALL THREE equations

• 2P + L + S = 14

• P + L + 3S = 15

• 3P + L + 2S = 22

• P + L +S = 14

• 2P + L + 2S = 22

Practice 9.2

​Matrix Addition & Subtraction

9.2 Notes Key.pdf - Google Drive

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Multiple Select

Select ALL TRUE statements.

• The matrix is a 2 x 3.

• The address of the number 2 is A₃₁

• The address of the number 1 is A₁₁

• The address of the number 5 is A₂₁

Multiple Choice

Select the correct dimensions.

• 3 x 3

• 3 x 2

• 2 x 3

• 2 x 2

Multiple Choice

What is D + B ?

• [ 11 7 ]

  [ 12 6 ]

  [ 11 5 ]

• [ 10 8]

  [ 10 8 ]

  [ 7 9 ]

• [ 34 18 ]

• You CANNOT add D and B.

Multiple Choice

What is B - D ?

• [-3 -5 ]

  [ 6 4 ]

  [ -5 -3 ]

• [ 3 5 ]

  [ -6 -4 ]

  [ 5 3 ]

• [ 0 4 ]

• You CANNOT subtract D and B.

Open Ended

Explain WHY you CANNOT calculate A + D.

Multiple Choice

Find C - A. What number is at the address m₁₂?

• 13

• 3

• 11

• It is not possible to subtract them.

Practice 9.3

​Matrix Multiplication

9.3 Notes KEY - Matrix Multiplication.pdf - Google Drive

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Multiple Choice

Problem 1

• [ 36 8 ]

  [ 10 30]

• [ 20 6 ]

  [ 7 17 ]

• [ 36 8 ]

  [ 5 15 ]

• Not here

Multiple Choice

Problem 2

• [ 40 20 ]

  [ 12 24 ]

• [ 14 9 ]

  [ 7 10 ]

• [ 40 20 ]

  [ 3 6 ]

• Not here

Multiple Choice

Problem 3

• [ 49 14 ]

  [ 21 7 ]

• [ 50 15 ]

  [ 24 10 ]

• [ 15 10 ]

  [ 14 10 ]

• Not here

Multiple Choice

Problem 4

• [ 12 7 ]

  [ 23 16]

• [ 13 8 ]

  [ 12 9 ]

• [ 12 7 ]

  [ 19 8 ]

• Not here

Multiple Choice

Problem 5

• [ 35 9 ]

  [ 40 24 ]

• [ 45 53 ]

  [ 58 60 ]

• [ 23 25 ]

  [ 24 24 ]

• [ 71 34 ]

  [ 82 34 ]

Multiple Choice

Problem 6

• [ 35 9 ]

  [ 40 24 ]

• [ 45 53 ]

  [ 58 60 ]

• [ 23 25 ]

  [ 24 24 ]

• [ 71 34 ]

  [ 82 34 ]

Open Ended

Problem 7

Explain WHY you ❌CANNOT multiply these two matrices.

⚡HINT: Check the dimensions!

​No need to answer here!
Just use the hint to help you answer.

⚡HINT: Matrix A should be a 5 x 2.

Question 8

​No need to answer here!
Just use the hint to help you answer.

⚡HINT: Matrix C should be a 5 x 2.

Question 9

⚡HINT: You should be using scalar multiplication and addition to solve.

Your final matrix should be 5 x 2.

Question 10

Poll

How do you FEEL NOW about using matrices to solve problems?

• I feel great! I can help a friend.

• I need some help, please.

• I get it, but need more practice

Poll

Which skill would you like to review again?

You may select more than one.

• Solving systems of equations (no matrix)

• Writing a system of equations from a word problem

• Solving a system

  (with a matrix)

• Adding or Subtracting matrices

• Multiplying matrices