已知x、y满足：x^2+y^2+6x-10y+34=0,求y-x的值
问题描述：
已知x、y满足：x^2+y^2+6x-10y+34=0,求y-x的值
答
x^2+y^2+6x-10y+34=0,
x^2+6x+9+y^2-10y+25=0
(x+3)^2+(y-5)^2=0
x+3=0,y-5=0
x=-3,y=5
则y-x=5-(-3)=5+3=8