Question

Literal equations Solve P=2(l+W) for l

Answer 1

                           P = 2(L +W)

Divide each side of the equation by 2 :    P/2 = L + W

Subtract  W  from each side :                  P/2 - W  =  L

Answer 2

$P=2(l+W)\\ l+W=\dfrac{P}{2}\\ l=\dfrac{P}{2}-W$