Answer:
x + 6 + x + 6 + x + 6 + x + 6 + x + 6 x + 6 + x + 6 + x + 6 = 120
aka 8(6 + x) = 120
48 + 8x = 120
you want to get 8x on one side so you will subtract 48 on both sides - whatever you do to obe side you must do on the other side.
8x = 72
now you want the x by its self so to undo multiplication you need to divide, and divide on both sides.
x = 9
Solution: x = 9