Subtracting and Scalar Multiplication of Matrices

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

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

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 orders must be equal.

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

• 
• 
• UNDEFINED

• 

Find -3A

• 
• 
• 
• Does Not Exist

Find (Y + Z) + 2X

• 
• 
• 
• Does Not Exist

Find -2C + 5D

• 
• 
• 
• Does Not Exist

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

What do m, n, p and q equal in this scalar matrix multiplication?

• m=8, n=9, p=-4, q=4 
• m=15, n = -45, p=20, q=-5
• m=20, n=-5, p=15, q=-45
• m=-5, n=20, p=-45, q=15