x-y/x+y=-1/2,x*x-xy-2y*y/x*x-3xy+2y*y的解是多少?同上,请将过程写出,

|x|/x+y/|y|+xy/|xy|= x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y xy-1+x-y x-y/x+y=-1/2,x*x-xy-2y*y/x*x-3xy+2y*y的解是多少?同上,请将过程写出, 已知x+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+x(xy+y)的值 .(x+y-2)(x+y-2xy)+(xy-1)^2 (x/x+y-x/y-x-2xy/x.x-y.y)/(1/x-1/y) 分式化简 若x+y=1,x不等于0则x+(2xy+y^2)/x/(x+y)/x= 当x=2 y=2分之1 时,代数式(x+y)(x-y)+(x-y)^-(x^-3xy ) (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) f(xy,x-y)=x^2+y^2+xy;f(x,y)/∂x;f(x,y)/∂y 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) (-x-y)(x^2+xy+y^2) 化简x^-y^/x^-2xy+y^ 2*(x-y)²(y-x)(xy) （x^2+xy/x-y)/（xy/x-y)计算 [(x+y)(x-y)-(x-y)^2-4xy]/2y,其中x=1,y=-1