Solve for X using the matrices below.

Question

2A + 4B = −2X

A=
((8,-5)
(9,0)
(5,-6))

B=
((0,7)
(4,0)
(-6,-1))

Answer 1

2A + 4B =
(16,-10) + (0,28) = (16,18)
(18,0) + (16,0) = (34,0)
(10,-12) + (-24,-4) = (-14,-16)
so, X = -1/2 times all that:
((-8,-9)
(-17,0)
(7,8))

Answer 2

oobleck got it!