Practice 7.5 Adding and Subtracting Matrices

• A

• B

• C

• D

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 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 B-A

• -4     0
  6     -1

• 1     0
  1     -4

• 4       0
  -6     1

• not possible because rows do not match columns

• A

• B

• C

• D

Given these matrices find C - D

• 
• 
• 
• NA

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

Perform the indicated operation

• 
• 
• 
• 
• not possible

• 
• 
• 
• Not enough info

• a

• b

• c

• d