Question

The length of a rectangle is three times its width. If the area of the rectangle is 48, what is its length?

Answer 1

l = 3w

A = lw

48 = 3w(w)
48 = 3w^2

16 = w^2

w^2 -16 = 0
(w-4)(w +4) =0
w = 4
l = 3w
l = 3(4) = 12

width = 4
length = 12