已知x=2+
,y=2-
,求
-
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ef5ea510b44c312e8241cf0e7f2d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ef5ea510b44c312e8241cf0e7f2d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05e2901fcedfdfa2fead0aa7c925a2f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dda38a96cb878e6c47c97d5e7fcc027.png)
更新时间:2018-03-08 19:24:21
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【知识点】 二次根式的化简求值