化简；(x-y)(x+y)+(x-y)²+(x+y)²

化简：（2x-y)²-4(x-y)(x+y) 因式分解:x²(x-y)+(y-x) {(x,y) |x|+|y| x>y?x:y 2.(x+y)²(x-y)²-(x-y)(x+y）(x²+y²) 化简 3(X-Y)²-4(X-Y)+7(X-Y)-6(X-Y)² (2x-y)²-4(x-y)(x+2y) (x-y)³+9(x-y)-6(x-y)² (x-y)³(x-y)²(y-x)等于多少 x²-y²+x+y 1、y-x/x²-y² 约分：y-x/x²-y²