Operations with Matrices

How many columns are in a 5 x 4 matrix?

• 5
• 4
• 20
• 9

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

• -3     1
  7     -1
• 1     0
  1     -4
• 4       0
  -6     0
• not possible because rows do not match columns

What are the dimensions of this matrix?

• 2 x 3
• 3 x 2
• 6 x 1
• 1 x 6

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  

find: B*A

• 47     30
  9     5
• 17     15
  42     35
• 10     25
  7     1
• not possible because rows do not match columns

You can multiply a 2X3 matrix by which matrix?

• 2X2
• 2X12
• 3X12
• 2X3

Find the product of the two matrices.

• undefined
• -3   16
  17   12
  8   -10
• 3   12 
  -15  -8
  -1   -3

In Matrix R (pictured) what element is a₂₃?

• 8
• 9.01
• 6
• 1

Find the product of the two matrices.

• 1   2
  6   -8
• -3   -5
  -5   -11
• -2     8
  -6   -12
• 2  -3
  5   -2