Summarize the following:
The formula is P=2l+2w{\displaystyle P=2l+2w}, where P{\displaystyle P} equals the perimeter of the rectangle, l{\displaystyle l} equals the length of the rectangle, and w{\displaystyle w} equals the width of the rectangle.  This method will only work if you are given the perimeter and length of the rectangle. You might also see the formula written as P=2(w+h){\displaystyle P=2(w+h)}, where h{\displaystyle h} equals the height of the rectangle and is used instead of length. The variables l{\displaystyle l} and h{\displaystyle h} refer to the same measurement, and the distributive property dictates that these two formulas, although arranged differently, will give you the same result. Make sure you substitute for the correct variables. For example, if you are trying to find the width of a rectangle that has a perimeter of 22 centimeters, and a length of 8 centimeters, your formula will look like this:22=2(8)+2w{\displaystyle 22=2(8)+2w}22=16+2w{\displaystyle 22=16+2w} To do this, you need to subtract the length from each side of the equation, then divide by 2. For example, in the equation 22=16+2w{\displaystyle 22=16+2w}, you would subtract 16 from each side, then divide by 2.22=16+2w{\displaystyle 22=16+2w}6=2w{\displaystyle 6=2w}62=2w2{\displaystyle {\frac {6}{2}}={\frac {2w}{2}}}3=w{\displaystyle 3=w} Don’t forget to include the unit of measurement. For example, for a rectangle with a perimeter of 22cm{\displaystyle 22cm} and a length of 8cm{\displaystyle 8cm}, the width would be 3cm{\displaystyle 3cm}.

Summary:
Set up the formula for perimeter of a rectangle. Plug the values for perimeter and length into the formula. Solve for w{\displaystyle w}. Write your final answer.