Matrix practice

What are the dimensions of this matrix?

• 4x3

• 3x4

• 3

• 4

How many rows are in a 7 x 3 matrix?

• 7

• 3

• 21

• 10

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 is the size of the matrix below?

• 0 x 1

• 1 x 0

• 3 x 3

• 3 x 0

a₂₃ = ?

• -3

• 5

• -9

• 2

What is the representation of the location of 5?

• a₁₂

• a₂₁

• a₂₅

• a₁₃

In Matrix R (pictured) what element is in the second row, third column?

• 8

• 9.01

• 6

• 1

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

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.

Subtract

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