The length of a rectangle is 2 inches more than 4 times the width. If the area of the rectangle is 20 square inches, find the length and the width.
width ---- x
length ---- 4x+2
x(4x+2) = 20
4x^2 + 2x - 20 = 0
2x^2 + x - 10 = 0
(x-2)(2x+5) = 0
x = 2 or x = -5/2, reject that negative
the width is 2 inches, and the length is 10 inches