Add Subtract Multiply Matrices

Subtract

• 3    -8
  0   -1

• 3   -4
  8  -13

• -3   8
  0    1

• 3   -8
  -8    1

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

Find 2A-3B

• -3 1

  7 -1

• 1 0

  1 -4

• -4 0

  6 -1

• -14 -5

  11 -3

When you multiply a matrix by the identity matrix, you obtain the

• inverse matrix.

• transpose matrix.

• Identity matrix

• original matrix.

When you multiply a matrix by the inverse matrix, you obtain the

• inverse matrix.

• transpose matrix.

• Identity matrix

• original matrix.

What is the Inverse of A? Show work by hand.

• 
• 
• Cannot Determine

• 

Find A-B

• -3     1
  7     -1

• 1     0
  1     -4

• -4       0
  6     -1

• not possible because rows do not 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.

What do w, x, y and z equal in this matrix subtraction?

• w = 13, x = 4, y = 7, z = 23

• w = 13, x = -4, y = 11, z = 23

• w = 13, x = 4, y = 11, z = 23

• w = 13, x = 4, y = 11, z = 17

find: B*A

• 47     30
  9     5

• 17     15
  42     35

• 10     25
  7     1

• not possible because rows do not match columns