Could someone help with my hw? :( use this inverse to solve the system.

7x-8y=-21
x-y=-2

First, you have to plug the coefficients (the left side) into a 2x2 matrix.
matrix A= [7 -8]
[1 -1]
Then, plug in the answers (the right side) to a 2x1 matrix.
Matrix B= [-21]
[ -2]
Multiply the inverse of Matrix A by the original form of Matrix B.

The solutions of the multiplication will be your x and y, in that order.