[(x+2y)²-(x+y)(x-y)-7y²】÷（2y）

求因式分解(x-y)²-2(x-y)³和（x+y）（x-y）-x（x-y） （x-2y）²+（2x-4y)(x+y)+(x+y)² (x-y)的四次方(x-y)-2(x-y)²(y-x）³等于? (2x-y)²-4(x-y)(x+2y) 化简：（2x-y)²-4(x-y)(x+y) ｛（x-y）²＋（x+y）（x-y）｝÷2x 急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy) [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y [(x+y)(x-y)-(x-y)²]÷(-2y)数学高手来 2.(x+y)²(x-y)²-(x-y)(x+y）(x²+y²) 若|x+2y-1|+y²+4y+4=0,求（2x-y）²-2（2x-y)(x+2y)+(x+2y)& 计算4（x+y）^5（x-y）^4÷[2（x+y）³*（y-x）²]