Let the perimeter of the rectangular garden be expressed as 2(L+W)
L = length of the garden
W = width of the garden
If the length of the garden is twice its width then L = 2W; W = L/2
P = 2(L+L/2)
Since the perimeter is L + 32 (One length of a rectangular garden that lies along a patio wall and the rest of the garden is enclosed by 32 feet of fencing.)