问题 解答题
先化简,再求值:[(x-y)2+(x-y)(x+y)]÷x,其中x=-1,y=
1
2
答案

[(x-y)2+(x-y)(x+y)]÷x,

=(x2-2xy+y2+x2-y2)÷x,

=(2x2-2xy)÷x,

=2x-2y,

当x=-1,y=

1
2
,原式=2×(-1)-2×
1
2
=-3.

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