you have to distribute -2 to (x-2)
so you get 4x-2x+4 = -9+5x-8
then you combine like terms
2x+4=5x-17
again combine like terms
21=3x
divide 3 to both sides to isolate the x
x=7
I really hope that this helped you out in a way :)
4x-2x+4=-9+5x-8
2x+4=-9-8+5x
2x+4=-17+5x
-4 -4
2x= -21+5x
-5x -5x
-3x=-21
/-3 /-3
x=7
