先化简，再求值： (1x−1x+2)⋅x2−42 ，其中x=3．_刷题宝

题干

先化简，再求值： (

1

x

−

1

x

+

2

)⋅−

x

2

4

2

，其中x=3．

上一题下一题 0.0难度选择题更新时间:2017-12-12 11:17:36

答案(点此获取答案解析）

解：

(\frac{1}{x} - \frac{1}{x + 2}) \cdot

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