Choice Bhoice D is the correct answer.

1. Start: $P = 2l + 2w$
2. Subtract 2l: $P - 2l = 2w$
3. Divide by 2: $w = \frac{P - 2l}{2}$ or $w = \frac{P}{2} - l$

Choice Bhoice A is incorrect because forgot to divide.

Choice Bhoice C is incorrect because sign error.

Choice Bhoice D is incorrect because this is equivalent to A, but A is the standard form shown.