题目内容
已知a,b,c,x,y,z,w为有理数.规定:符号
表示运算a-b+
(c≠0),符号
表示运算|xw-y2|.则
+
=
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/6a1b4878.png)
1 | c |
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/841b107f.png)
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/ba6ccde0.png)
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/80de5796.png)
-5
-5
(直接写出答案)分析:根据题中的新定义将所求式子化为普通运算,计算即可得到结果.
解答:解:根据题意得:
=2-3+1=0,
=4-9=-5,
则则
+
=0-5=-5.
故答案为:-5
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/ba6ccde0.png)
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/80de5796.png)
则则
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/ba6ccde0.png)
![](http://thumb.1010pic.com/pic3/upload/images/201307/55/80de5796.png)
故答案为:-5
点评:此题考查了代数式求值,弄清题中的新定义是解本题的关键.
![](http://thumb2018.1010pic.com/images/loading.gif)
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