已知（x^2-2xy+y^2)+(-2x+2y)+1=0,求x-y的值

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+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+2(xy+y)的值 已知X+Y=-1,xy=-2,求代数式-5(x+y)+(x-y)+(xy+y)的值 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x-3y=0,求（2x+y)/(x^2-2xy+y^2)*(x-y)的值 已知x-3y=0,求(2x+y)/(x^2-2xy+y^2)*(x-y)的值. 已知x-3y=0,求(2x+y)(x-y)/x^2-2xy+y^2的值 已知x-3y=0,求2x+y/x-2xy+y乘(x-y)的值 已知x^2+xy-2y^2=0 (x不等于0,y不等于0）,求x/y-y/x-(x^2+y^2)/xy的值