What is the solution of the matrix equation?

Hello from MrBillDoesMath!

The first choice ( -12, 20)

Discussion:

Using matrix multiplication we find the equations:

1x  + 1y = 8                     (A)

2x  + 3y = 36                   (B)

Next, compute

  2(A) - B  =>

         (2x + 2y) - (2x + 3y) = 2*8 - 36    =>

          (2x - 2x) + ( 2y-3y) = 16 - 36 =>

          -y = -20  =>

         y = 20

Substituting this y value in (A) gives

         x + 20 = 8 =>

         x = 8 - 20 =>

        x = -12

The answer is the first choice ( -12, 20)

Thank you,

MrB

I think the answer is D(?)