Unit 3 Test Review (Matrices)

Add

• 11    8
  -4     2
• 3     2
  -6    -6
• -3    2
  -4    -6
• 10    8
  -6    2

What is the size of the matrix below? Always do Rows x Columns.

• 3 x 4

• 4 x 3

Which element is located in A₂₃?

• -3

• 5

• -9

• 2

Subtract

• 3    -8
  0   -1

• 3   -4
  8  -13

• -3   8
  0    1

• 3   -8
  -8    1

Find A-B

• -3     1
  7     -1

• 1     0
  1     -4

• -4       0
  6     -1

• not possible because rows do not match columns

Multiply

• 20     15    -10
  30     -5         0

• -20      15     -10
  30     -5          0

• 1        8       3
  11     4        5

• 20     -15     10
  -30         5        0  

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.

Find the product of the two matrices.

• 17 12

  25 18

• 17 12

  12 6

• 17 12

  7 5

• 17 12

  10 12

Solve the system of equations: 

• ( -2, 4, 3)
• ( 2, 1, 6)
• No solution
• None of these

I can multiply a [3x4] matrix by which matrix?

• [3x4]

• [2x4]

• [4x7]

• [3x1]