how do i solve the system using substitution?

Question

Solve the system using substitution x=4y+8

                                                                 x=-5y-1

Answer 1

since they both =x, set them equal to each other 4y+8= -5y -1

then add 5y to both sides 9y + 8 = -1

subtract 8 from both sides 9y = -9

divide both sides by 9 and y= -1

then put -1 into y for either equation to get x

x = 4(-1) + 8   then x = 4

solution is (4, -1)