Question

初二化简题

[(x+y)(x-y)-(x-y)²+2y(x-y)]除以（-2y)

Answer 1

先将分子化简
[(x+y)(x-y)-(x-y)²+2y(x-y)]
=x²-y²-(x²+y²-2xy)+2y(x-y)
=-2y²+2xy+2y(x-y)
=2y(x-y)+2y(x-y)
=4y(x-y)
[(x+y)(x-y)-(x-y)²+2y(x-y)]除以（-2y)
=4y(x-y)/（-2y)
=2(y-x)

Answer 2

[(x+y)(x-y)-(x-y)²+2y(x-y)]除以（-2y)
可以写成：
[(x+y)(x-y)-(x-y)(x-y)+2y(x-y)]/（-2y)
提取公因式(x-y)：
[(x+y-x+y+2y）(x-y)]/（-2y)
化简的：
[4y(x-y)]/（-2y)
=-2(x-y)
=2y-2x

Answer 3

最讨厌这些，没事瞎折腾脑，学吧学吧最后走到社会啥用没有~~~~堪比古时四书五经

Answer 4

2y-2x