1. Transforming Formulas

ok i know you probably think im stupid for not getting this but....

i dont get
r=2s-8

solving for the s.

2. Well, all we have to do is make the s be on one side of the equation BY ITSELF, so we take our original problem:

$r = 2s - 8$

First, we add 8 to both sides of the equation:

$r + 8 = 2s - 8 + 8$

Notice what's left on the right side:

$r + 8 = 2s$

Now we divide both sides of the equation by 2:

$\frac{1}{2}r + 4 = 2s/2$

Look what's left:

$\frac{1}{2}r + 4 = s$

And problem solved.

All you have to do is move everything to the other side by doing the opposite to both sides of the equation.