x2+y2-4x-6y+13=0求分式y2-x2*xy
问题描述：
x2+y2-4x-6y+13=0求分式y2-x2*xy
*是除号 2是平方
答
x^2+y^2-4x-6y+4+9=0
(x^2-4x+4)+(y^2-6y+9)=0
(x-2)^2+(y-3)^2=0
x=2
y=3
(y^2-x^2)/xy
=(9-4)/6
=5/6
/是除号