已知x^2+y^2-2x-4y+5=0,求1/2（x-1）^2-xy

已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 已知x^2+y^2-4x+2y+5=0则x^y=? 已知x^2+4x+y^2+2y+5=0,则x^y= 已知{x-y+2>=0,x+y-4>=0,2x-y-5 已知x-y+2>=0,x+y-4>=4,2x-y-5 已知4x^2+y^2-4x+4y+5=0,求x,y 已知x²+4x+y-2y+5=0求x+2y 已知x²+4x+y²-2y+5=0,则x+y= 已知x²+y²-2x+4y+5=0,求x+y 已知|5x-y-8|+(7y-x+2)=0则4x+6y 已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知X^2+Y^2-2X-4Y+5=0,求分式Y/X-X/Y的值 已知x²+y²-2x-4y+5=0,求分式y/x-x/y的值. 已知x、y满足x²+y²+2x-4y+5=0,求x、y的值 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知x²+4y²-4x+4y+5=0,求：(x^4-y^4)/[(2x-y)(x+y)]*(2x-y)/(xy-y²)/[(x²+y²)²/y²]