Question

The length of a rectangle is 5 inches more than its width, x. The area of a rectangle can be represented by the equation x2 + 5x = 300. What are the measures of the width and the length?

Answer 1

width: 15 inches; length: 20 inches

Explanation:

The equation tells you the product of width (x) and length (x+5) is 300, so you're looking for factors of 300 that differ by 5.

300 = 1·300 = 2·150 = 3·100 = 4·75 = 5·60 = 6·50 = 10·30 = 12·25 = 15·20

The factors in the last pair on this list differ by 5, so we have ...

• width = 15 inches
• length = 20 inches