Solve for X using the matrices below.

Question

2A + 4B = −2X

A = 8 -5 and B = 0 7

1 0 2 0

9 -2 -2 -1

X = _____ _____

_____ _____

_____ _____

Answer 1

First multiply every element in the A matrix by two:

2*A = 16 -10

2 0

18 -4

Then multiply every element in the B matrix by four:

4*B = 0 28

8 0

-8 -4

2*A+4*B = 16 18

10 0

10 -8

Since 2*A+4*B=2*X, the X matrix is the result of dividing each element in 2*A+4*B matrix by 2. Therefore,

X = 8 9

5 0

5 -4