题目内容
求未知数X
![]() ![]() ![]() ![]() | ![]() |
解:(1)
x+
x-
x=
,
(
+
-
)x=
,
x=
,
x×
=
×
,
x=1;
(2)
:
=x:
,
x=
×
,
x×8=
×8,
x=
.
分析:(1)原式变为 (
+
-
)x=
,即
x=
,两边同乘
即可;
(2)先根据比例的性质改写成
x=
×
,再根据等式的性质,两边同乘8即可.
点评:此题考查了运用等式的性质解方程,即等式两边同加上或同减去、同乘上或同除以一个数(0除外),两边仍相等,同时注意“=”上下要对齐.
![](http://thumb.1010pic.com/pic5/latex/168.png)
![](http://thumb.1010pic.com/pic5/latex/13.png)
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
(
![](http://thumb.1010pic.com/pic5/latex/168.png)
![](http://thumb.1010pic.com/pic5/latex/13.png)
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/1159.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/1159.png)
x=1;
(2)
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/112.png)
![](http://thumb.1010pic.com/pic5/latex/63.png)
![](http://thumb.1010pic.com/pic5/latex/112.png)
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/63.png)
![](http://thumb.1010pic.com/pic5/latex/112.png)
![](http://thumb.1010pic.com/pic5/latex/13551.png)
x=
![](http://thumb.1010pic.com/pic5/latex/36.png)
分析:(1)原式变为 (
![](http://thumb.1010pic.com/pic5/latex/168.png)
![](http://thumb.1010pic.com/pic5/latex/13.png)
![](http://thumb.1010pic.com/pic5/latex/365.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/927.png)
![](http://thumb.1010pic.com/pic5/latex/1159.png)
(2)先根据比例的性质改写成
![](http://thumb.1010pic.com/pic5/latex/112.png)
![](http://thumb.1010pic.com/pic5/latex/96.png)
![](http://thumb.1010pic.com/pic5/latex/63.png)
点评:此题考查了运用等式的性质解方程,即等式两边同加上或同减去、同乘上或同除以一个数(0除外),两边仍相等,同时注意“=”上下要对齐.
![](http://thumb2018.1010pic.com/images/loading.gif)
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