P = 2(L + W)
L = W + 4
A = 5P - 4
P = 2(W + 4 + W)
P = 2(2W + 4)
P = 4W + 8
A = 5(4W + 8) - 4
A = 20W + 36
A = L * W
A = W(W + 4)
A = W^2 + 4W
W^2 + 4W = 20W + 36
W^2 - 20W + 4W - 36 = 0
W^2 - 16W - 36 = 0
(W + 2)(W - 18) = 0
W - 18 = 0
W = 18
L = W + 4
L = 18 + 4
L = 22
A = L * W
A = 18 * 22
A = 396
P = 4W + 8
P = 4(18) + 8
P = 72 + 8
P = 80
length = 22, width = 18, area = 396, perimeter = 80