x^2-4xy+5y^2+6y+9=0,x+y=
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*
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
x*-2xy+3y*=9 4x*-5xy+6y*=30
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
已知x,y>0 2x+y+3=xy 求5x+4y最小值
已知x^3+xy^2+x+x^2y+y^3+y=0,求5x-6y/3x+4y的值.
已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
[-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y-
已知x²+y²-2x+4y+5=0,求x²-9y²/x²+6xy+9y
已知:x²-6xy+9y²=0,求代数式3x+5y/4x²-y²×(2x+y)的
已知x>0,y>0,x+根号xy-6y=0,求4x+5根号xy-6y分之x+2根号xy