Length = x
width = x-2
area of a rectangle = L x W
area = 48
so you have x * (x-2) = 48
simplify the left side :
x^2 -2x = 48
subtract 48 from both sides:
x^2 - 2x -48 = 0
now factor the polynomial:
(x-8) (x+6)
solve for x:
x-8 = 0. x = 8
x+6 = 0, x=-6
you can't have a length which is a negative number so x ( the length) = 8 feet
the width = 8-2 = 6 feet
8 * 6 = 48 so this is true.
Length = 8 feet, width = 6 feet