Matrices

find: B*A

• 47     30
  9     5

• 17     15
  42     35

• 10     25
  7     1

• not possible because rows do not match columns

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How many elements are there in a 3 x 3 matrix?

• 9

• 15

• 12

• 6

Find the sum.

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Find the difference.

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Find the product.

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Find the product.

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The image shows a students' work for adding two matrices together. What was their error?

• You cannot add matrices of different sizes together.

• They added incorrectly.

• They subtracted incorrectly.

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