已知x^2-2xy+2y^2-y+4分之1=0,则x^5乘y的负5次方等于多少?

题目

已知x^2-2xy+2y^2-y+4分之1=0,则x^5乘y的负5次方等于多少?

答案

x^2-2xy+y^2+y^2-y+1/4=0
(x-y)^2+(y-1/2)^2=0
(x-y)^2>=0
(y-1/2)^2>=0
(x-y)^2+(y-1/2)^2>=0
(x-y)=0
(y-1/2)=0
x=y=1/2
x^5y^(-5)
x^5*x^(-5)=1