Question

Given the following matrices A and B,

A=[x y B=[2
-8 −y] and 1]

if the product of the matrices AB=[−23
x]

, find a value of x that satisfies these conditions.

is it -7?

thank you

Answer 1

AB =

[2x+y]
[-16-y]
so if that is [-23 x] you have
2x+y = -23
x+y = -16
so x = -7 looks good