The length of a rectangle is 2 inches less than twice its width. the area of the rectangles is 40 square inches find the length and width.
Lenght (L)
Width (W)
Area (A) = 40 sq in
L = 2W - 2 ← call this eq1
A = L x W ← call this eq2
substitute eq1 to eq2
A = (2W - 2) x W
40 = 2W² - 2W
2W² - 2W - 40 = 0
divide by 2
W² - W - 20 = 0
W = [-(-1) ±√1 - 4(-20)]/2(1)
w = 1 ±√81
W = 1±9/2
W = [1 + 9 ] / 2
W = 5
Substitute W = 5 to eq1
L = 2W - 2
L = 2(5) - 2
L = 10 - 2
L = 8