Question

S=L (1 - r), for r
This is all it says, you are solving for r, the instructions just say solve for r

Answer 1

Solving for r is the same as isolating it. Since we have (1-r) being multiplied by L, we want to divide it out so we can work with (1-r), so:

$\frac{S}{L}=1-r$

Now, we want to make -r positive, so we multiply both sides by negative 1:

$-\frac{S}{L}=r-1$

Now, to isolate r we want to add 1 to both sides, so:

$1-\frac{S}{L}=r$

and we're done.