The width w of a rectangular swimming pool is 7x2. The area A of the pool is 7x3 - 42x2. What is an expression for the length of the pool? Show your work.

A = length · width

7x3 - 42x2 = L (7x2) Factor left side

7x2 (x - 6) = L (7x2) Divide both sides by 7x2

x - 6 = L

The length of the pool is x - 6.

Note: Length is always longer than width. Although the algebra is correct, it is doubtful that x - 6 is greater than 7x2.