题目内容
解方程.
8x+4×0.6=8 | 1-![]() ![]() ![]() |
解:①8x+4×0.6=8,
8x+2.4=8,
8x+2.4-2.4=8-2.4,
8x=5.6,
8x÷8=5.6÷8,
x=0.7;
②1-
x=
,
1-
x+
x=
+
x,
x+
-
=1-
,
x=
,
x÷
=
÷
,
x=
;
③x-
=12,
x=12,
x÷
=12÷
,
x=15.
分析:①先计算出4×0.6=2.4,再根据等式的性质,方程的两边同时减去2.4,再除以8即可;
②根据等式的性质,方程的两边同时加上
x,再减去
、除以
即可;
③先算出
x-
得数是
x,再根据等式的性质,方程的两边同时除以
即可.
点评:此题考查利用等式的性质解方程,注意等号对齐.
8x+2.4=8,
8x+2.4-2.4=8-2.4,
8x=5.6,
8x÷8=5.6÷8,
x=0.7;
②1-
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
1-
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/36.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/36.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
x=
![](http://thumb.1010pic.com/pic5/latex/2367.png)
③x-
![](http://thumb.1010pic.com/pic5/latex/1881.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
x=15.
分析:①先计算出4×0.6=2.4,再根据等式的性质,方程的两边同时减去2.4,再除以8即可;
②根据等式的性质,方程的两边同时加上
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
③先算出
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/1881.png)
![](http://thumb.1010pic.com/pic5/latex/14.png)
![](http://thumb.1010pic.com/pic5/latex/14.png)
点评:此题考查利用等式的性质解方程,注意等号对齐.
![](http://thumb2018.1010pic.com/images/loading.gif)
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