The length of a rectangle is 1 inch less than twice the width. the area is 21 inches what is the length?

Width = w

length = 2w-1

Area = length * width

21 = (2w-1) * w

21 = 2w² - w

2w² - w - 21 = 0

2w² + 6w - 7w - 21 = 0

2w (w+3) - 7 (w+3) = 0

(2w-7) (w+3) = 0

2w-7 = 0

w = 7/2 = 3.5 inch

length = 3.5*2 - 1 = 6 inch