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

ian gone lie this got me confused

step-by-step explanation:

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40