Chapter 3 - Equations and Problem Solving - 3.2 - Equations and Problem Solving - Problem Set 3.2 - Page 106: 45

w = $\frac{P}{2}-l$

Using the properties of equality, we obtain: P = 2l + 2w $\frac{P}{2}$ = $\frac{2l}{2}$ + $\frac{2w}{2}$ Divide both sides by 2 $\frac{P}{2}$ = l + w $\frac{P}{2}$ - l = l - l + w Subtract l from both sides w = $\frac{P}{2} - l$