Practice: Lesson 4 Matrix Addition and Subtraction Practice

How many rows are in a 7 x 3 matrix?

• 7
• 3
• 21
• 10

Find A+B

• 8     10
  8      1 
• 12     25
  7     1
• 10     30
  0     1
• can't add two together because the rows dont match columns

What must be true in order to ADD two matrices?

• They must be square.
• The dimensions must be equal.
• The determinant can't equal 0.
• The column of the 1st must equal the row of the 2nd.

Subtract

• -5
  -8
  3
  10
• -9
  8
  3
  2
• 5
  -8
  3
  10
• -5
  8
  3
  2

Subtract

• 3    -8
  0   -1
• 3   -4
  8  -13
• -3   8
  0    1
• 3   -8
  -8    1

What are the dimensions of this matrix?

• 2 x 3
• 3 x 2
• 6 x 1
• 1 x 6

What values of x and y make the equation true?

• x = 5

  y = -2

• x = 3

  y = -5

• x = 9

  y = 10

• x = 16

  y = -5

Given these matrices find D-A

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• NA

Given these matrices find C - D

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• NA

What is the value of the variable in the equation?

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