Chapter 2 - Solving Equations - Common Core Cumulative Standards Review - Selected Response - Page 159: 11

D: $w=(P-2l)/2$

We need to get the w alone. Thus, we cancel out the addition by subtracting $2l$ on both sides. This leaves us with the equation $P-2l=2w$. In order to cancel out multiplication, we use division, so we divide both sides of the equation by 2 to get that $w=(P-2l)/2$