x²+y²+2x-6y+10=0(x²+2x+1)+(y²-6y+9)=0(x+1)²+(y-3)²=0∴{x+1=0 y-3=0∴x=-1,y=3x+y=2
x^2+y^2+2x-6y+10=0 →(x+1)^2 +(y-3)^2=0 →x+1=0且y-3=0 →x+y=2
