(x^-2-y^-2)÷(x^-1+y^-1)+1/y-1/x

[(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² [(-2x-y)^2-(2x+y)(2x-y)]÷2y-1/2y (x-y/1-x+y/1)÷2y/y-x计算错了，是(1/x-y-1/x+y)÷2y/y-x 先化简,再求值:y(x-y)-x(x+y)/x²-y²÷x²+y²/x+y,其中x=2,y=-1 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x [(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y 1-[(x-y)/(x+2y)]÷[(x+y)(x-y)/(x+2y)²] 1-[(x-y)/(x+2y)]÷[(x+y)(x-y)/(x+2y)²]= 1／2x－（x+y／2x -x-y）÷（x+y) 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 化简：[(2x-y)平方+（2x+y)(2x-y)-4x(x-y+1)]÷2x x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (x+y)-(x-y)^3÷(x-y)(x+y)×2y化简e , 1、y-x/x²-y²2、(x-y)(y-z)(z-x)/(z-y)(y-x)(x-z) 化简y(x+y)+(x+y)(x-y)-x^2 (x+y)(x-y)+(x-y)^2-(6x^2×y÷2y-2xy^2÷2y)其中x=-3,y=1/3 先化简,再求值[(2x+y)^2-(2x+y)(2x-y)-y(5x+y)]÷(1/2y),其中x-y=2 (x-y)(2x-y-1)