题目内容
二元一次方程组
的解x、y的值是一个等腰三角形两边的长,且这个等腰三角形的周长为5,求腰的长.
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/201209231420130872593.png)
解:![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/201209231420131562330.png)
①若x、y都为腰,则x=y,
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/201209231420132275469.png)
②若x为腰、y为底,则2x+y=5,
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/201209231420132975406.png)
③若y为腰、x为底,则x+2y=5,(3m﹣3)+2(﹣m+3)=5,m=2,x=3,y=1,
不符合题意,舍去所以:等腰三角形的腰长为
或
.
故填
或
.
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/201209231420131562330.png)
①若x、y都为腰,则x=y,
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/201209231420132275469.png)
②若x为腰、y为底,则2x+y=5,
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/201209231420132975406.png)
③若y为腰、x为底,则x+2y=5,(3m﹣3)+2(﹣m+3)=5,m=2,x=3,y=1,
不符合题意,舍去所以:等腰三角形的腰长为
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/20120923142013364642.png)
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/20120923142013429619.png)
故填
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/20120923142013494642.png)
![](http://thumb.1010pic.com/pic1/upload/papers/c02/20120923/20120923142013559619.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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