已知x^2-2xy+y^2+x+y+1=0
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
已知实数x,y满足x²+y²-xy+2x-y+1=0 求x y
已知3x*+xy-2y*=0,求(x/y)-(y/x)-(x*+y*)/(xy)的值.*是平方
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知x^2+y^2+x^2y^2-4xy+1=0 求(x-y)^2008-(xy)^2008
已知X²+Y²+X²Y²-4XY+1=0 求:(X-Y)^2008-(XY)^2
已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y)
已知y-x-2xy=0,求3x+xy-3y/y-xy-x的值
已知y-x-2xy=0,求(3x+xy-3y)\(y-xy-x)的值
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
已知:xy+x=-1,xy-y=-2.