The length of a rectangle is 6 inches less than 3 times its width. Find the dimensions of the rectangle if its area is 45 square inches.

Answer 1

W = X in.
L = (3x - 6) in.

A = L*W = (3x-6)X = 45,
3x^2 - 6x = 45
3x(x-2) = 45,
x(x-2) = 15,
x^2 - 2x - 15 = 0
(x-5)(x+3) = 0,
x-5 = 0,
x = 5 in.

x+3 = 0,
x = -3.

Solution Set: x = 5, and x = -3.

Select + value of X:
x = 5

W = x = 5 in.
L = 3x-6 = 3*5 - 6 = 9 in.