The length of a rectangle is 5 more inches than twice a number. The width is 4 inches less than the same number. If the area of the rectangle is 15, find the number.

Answer 1

L = 2n+5

W=n-4

Area =LW = (2n+5)(n-4) = 15

2n² - 3n - 20 = 15

(2n+7)(n-5) =0

The minus root is extraneous and the number is 5.

L=15 and W = 1