To start, let's add on the first side to get 3x + 6x - 6 = 9x - 6. For the second side, we need to distribute the 4 to get 4(2x) + 4(-2), or 8x + (-8) or 8x - 8. Setting these equal, we subtract 8x from both sides to get x - 6 = -8, and adding 6 to both sides gives x = -2.
