## Intermediate Algebra for College Students (7th Edition)

$l=\dfrac{A-2wh}{2w+2h}$
Subtract $2wh$ on both sides to find: $A-2wh=2lw+2lh$ Factor out $l$ on the right side to find: $A-2wh=l(2w+2h)$ Divide by $2w+2h$ on both sides to find: $\dfrac{A-2wh}{2w+2h} = l \\l=\dfrac{A-2wh}{2w+2h}$