x* (y*6/99) + y* (6*x/99) + 6*(xy/99) = x+y+7
(99x+y*6)/99 + (99y+6*x)/99 + (99*6 + xy)/99 = x+y+7 / *99
99x + 10y + 6 + 99y + 60 + x + 594 + 10x + y = 99x + 99y + 693
110x - 99x + 110y - 99y + 660 = 693
11x + 11y = 33 / impartim la 11
x + y = 3
daca x=1 atunci y=2
x=2 y=1
deci avem perechile (1,2) si (2,1)