问题 解答题
(1)计算:
6
1
6
-
6

(2)先化简,再求值:[(x+y)2-y(2x+y)-8x]÷2x,其中x=-2.
答案

(1)原式=1-6=-5;

(2)原式=[(x+y)2-y(2x+y)-8x]÷2x

=[x2+2xy+y2-2xy-y2-8x]÷2x

=(x2-8x)÷2x

=

x(x-8)
2x

=

x-8
2

当x=-2时,原式=

-2-8
2
=-5.

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