Volume of a rectangular prism = 40 cubic feet.
Volume of a rectangular prism = length width height
width = x
length = 1 foot greater than its width = x + 1
height = 2 feet less than its width = x - 2
l w h = 40 ft³
(x+1) x (x -2) = 40
(x² + x)(x-2)
x³ - 2x² + x² + 2x = 40
x³ - x² + 2x - 40 = 0
solve for the value of x. I used the calculator to get the volume.
width = x = 4
length = x + 1 = 4 + 1 = 5
height = x - 2 = 4 - 2 = 2
V = 4 5 2
V = 20 * 2
V = 40 ft³
