x平方-6x+y平方+10y+34=0
x^2-6x+y^2+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
所以x平方+3x除以2xy+2y
=(x^2+3x)/(2xy+2y)
=(9+9)/(-30-10)
=18/(-40)
=-9/20