xy+y=10x+2027
xy-10x+y=2027; ( -10 si in stanga si in dreapta)
x(y-10)+(y-10)=2027-10
(y-10)(x+1)=2017
2017 e prim
(x+1)(y-10)=1·2017
x+1=1; x=0 si y-10=2017; y=2027
(x+1)(y-10)=2017·1
X+1=2017; x=2016 si y-10=1; y=11
(x,y)={(0,2027), (2016,11)}