數學題:求長方形的面積?

let the width and length be x and y

xy=2x+2y
xy-2y=2x
y(x-2)=2x
y=2x/(x-2)

where x and y and positive integer.
http://www.imagehosting.com/show.php/1571010_.jpg

x=3, y=6 or x=4 ,y=4 or x=6 ,y=3

so the area is 18 or 16

If X=Lenght, Y=Width, Z=Area / 周界

Area: Z=XY
周界: Z=2X+2Y