题目内容
若(x-3) 2=x2+kx+9,那么k的值是
- A.-6
- B.-3
- C.6
- D.-9
A
试题分析:先根据完全平方公式去括号,再比较等式两边即可判断.
∵![](http://thumb.1010pic.com/pic5/upload/201309/522466711d442.png)
∴![](http://thumb.1010pic.com/pic5/upload/201309/5224667142b8c.png)
故选A.
考点:等式的性质
点评:解答本题的关键是熟练掌握完全平方公式:![](http://thumb.1010pic.com/pic5/upload/201309/5224667167b6d.png)
试题分析:先根据完全平方公式去括号,再比较等式两边即可判断.
∵
![](http://thumb.1010pic.com/pic5/upload/201309/522466711d442.png)
∴
![](http://thumb.1010pic.com/pic5/upload/201309/5224667142b8c.png)
故选A.
考点:等式的性质
点评:解答本题的关键是熟练掌握完全平方公式:
![](http://thumb.1010pic.com/pic5/upload/201309/5224667167b6d.png)
![](http://thumb.1010pic.com/pic5/upload/201309/522466718de9b.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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