I see that you solved it, but here are some pointers for the future:
Always get the equation into y = mx + b so it will generally be either add/subtract the x, and then divide out the y to get it alone. Also, y = mx + b can also look like y = mx - b or y = b
If you ever have a negative y=, simply flip the sign of all of the equation. Example: x - y = 4 : I would subtract x but that would leave me with -y = -x+4, so flip all of the signs so it reads y = x -4
Hopefully this helps!