若x^2+y^2+2x-6y=10=0,则x-y=

问题描述:

若x^2+y^2+2x-6y=10=0,则x-y=

(x+1)^2+(y-3)^2=0
x=-1 y=3 x-y=-4
谢了过程(x+1)^2=x^2+2x+1(y-3)^2=y^2-6y+9