Adding and Subtracting Matrices

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.

Given these matrices find C - D

• 
• 
• 
• NA

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

Subtract

• -5
  -8
  3
  10

• -9
  8
  3
  2

• 5
  -8
  3
  10

• -5
  8
  3
  2

• a

• b

• c

• d

• A

• B

• C

• D

• 
• 
• 
• Not enough info

Find B-A

• -4     0
  6     -1

• 1     0
  1     -4

• 4       0
  -6     1

• not possible because rows do not match columns

Given these matrices find D - A

• 
• 
• 
• NA

Find Z - W

• 
• 
• 
• Does Not Exist