How can i find all integers to this equation? 3(x+y)-xy=0 I allready found just by tring that if x=y then its 6 and x=12 ,y=4 (x=4 and y=12) I think that there are more, but how can i find all of them? PS. the first task was: 1/x + 1/y = 1/3 and then i had to find all integers. Thank you for your help! Sorry for my bad english.