(x+y)ﾁ0ﾅ5(xﾁ0ﾅ5-xy+y)ﾁ0&#

若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y* 若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值 已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y) 已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy 已知x>0,y>0,且x+6y=5根号xy,求(2x+根号xy-y)分之(x+根号xy+2y)的值 已知x>0y>o且x-5根号xy-6y求(x-2根号xy+y)/x+根号xy-2y 已知（x+2）^2+|x+y+5|=0,求3x^2y-[2x^2y-(2xy-x^2y)-4x^2]-xy 已知(x+2)^2+|x+y+5|=0,求3x^2y+{-2X^2y-[-2xy+(x^2y-4x^2)]-xy} 已知x2+y2-2x+4y+5=0,求(x^4-y^4)/(2x^2+xy-y^2)·[(2x-y)/(xy-y^2)] 已知y=3xy+x,求代数式2x+5xy-2y/x-2xy-y的值(xy≠0) 已知x^2+y^2-4x+6y+13=0求(xy+y^2/5x^2-5xy+xy+y^2)·（5/x+y）-（y/x-y