I need help finding the dimension

Question

The perimeter of a rectangle is 20 in, and it’s area is 16 sq inches . Find the dimension of the rectangle .

Answer 1

2L + 2W = 20 -> L + W = 10 -> L = 10 - W

L * W = 16

replace L with (10 - W)

W (10 - W) = 16

-W² + 10W = 16

W² + 10W - 16 = 0

factor the above equation

(W - 8) (W - 2) = 0

W = 8 or 2

L = 2 if W = 8, and L = 8 if W = 2