题目内容
解方程.
-X=
-
=
.
解:(1)
-X=
,
-X+X=
+X,
+X=
,
+X-
=
-
,
X=
;
(2)
+X=4,
+X-
=4-
,
X=3
;
(3)
-
=
,
X+
=
,
X+
-
=
-
,
X=
.
分析:(1)根据等式的性质,两边同加上X,得
+X=
,两边再同减去
即可;
(2)根据等式的性质,两边同减去
即可;
(3)先求出
-
=
,根据等式的性质,两边同减去
即可.
点评:在解方程时应根据等式的性质,即等式两边同加上、同减去或同乘上、同除以某一个数(0除外),等式的两边仍相等,同时注意等号上下要对齐.
![](http://thumb.1010pic.com/pic5/latex/602.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/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)
X=
![](http://thumb.1010pic.com/pic5/latex/50225.png)
(2)
![](http://thumb.1010pic.com/pic5/latex/1261.png)
![](http://thumb.1010pic.com/pic5/latex/1261.png)
![](http://thumb.1010pic.com/pic5/latex/1261.png)
![](http://thumb.1010pic.com/pic5/latex/1261.png)
X=3
![](http://thumb.1010pic.com/pic5/latex/6.png)
(3)
![](http://thumb.1010pic.com/pic5/latex/203626.png)
![](http://thumb.1010pic.com/pic5/latex/48628.png)
![](http://thumb.1010pic.com/pic5/latex/35.png)
X+
![](http://thumb.1010pic.com/pic5/latex/2788.png)
![](http://thumb.1010pic.com/pic5/latex/35.png)
X+
![](http://thumb.1010pic.com/pic5/latex/2788.png)
![](http://thumb.1010pic.com/pic5/latex/2788.png)
![](http://thumb.1010pic.com/pic5/latex/35.png)
![](http://thumb.1010pic.com/pic5/latex/2788.png)
X=
![](http://thumb.1010pic.com/pic5/latex/36.png)
分析:(1)根据等式的性质,两边同加上X,得
![](http://thumb.1010pic.com/pic5/latex/597.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/597.png)
(2)根据等式的性质,两边同减去
![](http://thumb.1010pic.com/pic5/latex/1261.png)
(3)先求出
![](http://thumb.1010pic.com/pic5/latex/36.png)
![](http://thumb.1010pic.com/pic5/latex/48628.png)
![](http://thumb.1010pic.com/pic5/latex/2788.png)
![](http://thumb.1010pic.com/pic5/latex/2788.png)
点评:在解方程时应根据等式的性质,即等式两边同加上、同减去或同乘上、同除以某一个数(0除外),等式的两边仍相等,同时注意等号上下要对齐.
![](http://thumb2018.1010pic.com/images/loading.gif)
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