xy-3x-2y-3=0 => xy-3x-2y=3 => x(y-3)=2y+3 =>
=> y-3|2y+3, y-3|y-3 => y-3|2y-6 => y-3|9 => y-3∈{1, 3, 9} => y∈{4, 6, 12}.
Analizezi cazurile etc e5c
