To help further, this equation is in Standard Form:
Ax+By=C
8x-2y=18
Using the literal equation (the one with variables) you can simplify down into Slope-Intercept Form, y=mx+b, and you end up with this:
y=(-A/B)x+(C/B)
Therefore, you can substitute m with -A/B and b with C/B. Even though you already have the answer, I hope this helps you in future use.