Note that (2-x)(2+y)>2(y-x) is equivalent to xy < 4.
I really don't have any clue as to how to start doing this question...I'd love it if you could help by pointing me in the right direction (and not just solving it for me).
Here`s the question:
S={(x,y)eN^2: (2-x)(2+y)>2(y-x)
T={(1,1),(1,2),(1,3),(2,1),(3,1)}
Prove that S=T. I know that have to prove each set is contained in the other, I just don't know how to go about doing that