(x-y)(x+y)-(x-2y)(2x+y)请问怎么化简.

1、x(x-y)(x+y)-x(x+y)^2 2xy/(x+y)(x+y)与x/(x+y)(x-y)怎么通分 [3x^2-(x+y)(y-x)][2(-x-y)(y-x)+2x^2+3y^2]怎么化简? 3(x-y)-2(x+y)-5(x-y)+4(x+y)+3(x-y) 化简合并同类项 (1)(x^2/x)-y-x-y 化简求值:x/[9(x-y)^2]*[(x^2-y^2)/(x+y)]+{[(x^2+2)/(x+y)]-2} 【(x-y)^2+(x+y)(x-y)】除以 2x {(x,y) |x|+|y| x>y?x:y [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y (-2x+6y)的平方-(3x+2y)(2x-3y)+(-9y)*4怎么化简 谁帮我化简：[(x+y)(x-y)-(x+y)^2-2y(x-y)-2xy]÷xy