We want to get c all by itself on one side of the equation. Usually variables go on the left side, so let's flip the equation around.
c/9=-8
If we multiply c/9 by 9, the 9 will cancel out because if you divide by 9 and then multiply by 9 it just equals 1. We can do this to isolate the c, but whatever you do to one side of the equation, you have to do to the other. So, we multiply both sides by 9.
