## Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$l=2w-P$
$\bf{\text{Solution Outline:}}$ To solve the given equation, $w=\dfrac{P+l}{2}$ for $l ,$ use the properties of equality to isolate the variable. $\bf{\text{Solution Details:}}$ Using the properties of equality to isolate the variable, the equation above is equivalent to \begin{array}{l}\require{cancel} w=\dfrac{P+l}{2} \\\\ 2(w)=2\left( \dfrac{P+l}{2} \right) \\\\ 2w=P+l \\\\ 2w-P=l \\\\ l=2w-P .\end{array}