Matrices

How many columns are in a 5 x 4 matrix?

• 5
• 4
• 20
• 9

In Matrix R (pictured) what element is a₂₃?

• 8
• 9.01
• 6
• 1

Add

• 11    8
  -4     2
• 3     2
  -6    -6
• -3    2
  -4    -6
• 10    8
  -6    2

Find A-B

• -3     1
  7     -1
• 1     0
  1     -4
• -4       0
  6     -1
• 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

What comes first in the order?

• Row
• Column

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  

Multiply

• 25
  25
  5
• -25
  25
  -5
• -10
  -10
  -6
• 10
  10
  6

Can the operation be performed?

• Yes
• No
• Sometimes
• Who knows

What are the dimensions of this matrix?

• 3x1
• 1x3
• 3x3
• 1x1