a rectangle has a length of 21 feet less than 3 times its width. if the area of the rectangle is 990 square feet find the length of the rectangle

Question

a rectangle has a length of 21 feet less than 3 times its width. if the area of the rectangle is 990 square feet find the length of the rectangle

Answer 1

w( 3w - 21) = 990

3w² - 21w - 990 = 0

w² - 7w - 330 = 0

(w - 22)(w + 15) = 0

In order for the left side to equal 0, one of the factors must equal 0.

w - 22 = 0

w = 22

l = 3(22) - 21

l = 66 - 21

l = 45

w + 15 = 0

w = -15

Because we measure in positive values, we disregard this "answer."