化简1/2x-1/x+y（x+y/2x-x-y）

化简 3x(x^2-x-1)-(x+1)(3x^-x) X^3(x-y)+x(y-x) 化简y(x+y)+(x+y)(x-y)-x^2 2x分之1- x+y分之1(2x分之x+y -x-y)化简 化简1/2x-1/x+y（x+y/2x-x-y） 化简(2x+y)(2x-y)-(x+2y)(x-2y-1) [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y 1/(x-y)+1/(x+y)+2x/(x^2+y^2)+4x^3/(x^4+y^4)化简 化简：[(2x-y)平方+（2x+y)(2x-y)-4x(x-y+1)]÷2x (x/x+y-x/y-x-2xy/x.x-y.y)/(1/x-1/y) 分式化简 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x 1、y-x/x²-y²2、(x-y)(y-z)(z-x)/(z-y)(y-x)(x-z) x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² (x-y)(2x-y-1) 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 化简：y=|x-1|+|x+2| 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值