x²+y²-4x+6y+10=-3 x²-4x+y²+6y+13=0 (x²-4x+4)+(y²+6y+9)=0 (x-2)²+(y+3)²=0 O   suma    de    patrate    este    0   daca    toti   termenii    sumei    suint   0 x-2=0 =>x=2 y+3=0=>  y=-3 (x-y=2-(-3)=2+3=5 (x-y)³=5³=125