先化简,再求值:
,其中x=2019.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfa055011fd5f34f65e3825d98d48243.png)
18-19八年级下·吉林长春·期末 查看更多[2]
更新时间:2019-09-02 12:09:14
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相似题推荐
解答题-计算题
|
较易
(0.85)
【推荐1】(1)计算:
;
(2)先化简
,然后从
,0 ,1 ,2 中选取一个你喜欢的数作为 x的值代入求值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce109b1405e355036d18d0cdf902227f.png)
(2)先化简
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce2994900598cda1861f0a96173886eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acbc6a613224461ade69362d46550474.png)
您最近一年使用:0次
解答题-计算题
|
较易
(0.85)
【推荐2】小明解答:化简
的过程如下,试指出解答过程中错误步骤的序号,写出正确的解答过程,并求出当x
1时代数式的值.
解:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43e33a2746170702950a5608be0538da.png)
=![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3863440b9e7b52e8b892b25636127d09.png)
①
=
②
=![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3309c3d142e95e0f5b0db717f19a767e.png)
③
=![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12836ce48e772ff33e5f5ab2b9245390.png)
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43e33a2746170702950a5608be0538da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9b4c5e1020ea79072419cc39e382fb8.png)
解:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43e33a2746170702950a5608be0538da.png)
=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3863440b9e7b52e8b892b25636127d09.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a633fd25ab73aa9d7bf128b92f2e8c1.png)
=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3309c3d142e95e0f5b0db717f19a767e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12836ce48e772ff33e5f5ab2b9245390.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
您最近一年使用:0次