解:(1)
![](http://thumb.1010pic.com/pic5/latex/602.png)
-2X=
![](http://thumb.1010pic.com/pic5/latex/96.png)
,
![](http://thumb.1010pic.com/pic5/latex/602.png)
-2X+2X=
![](http://thumb.1010pic.com/pic5/latex/96.png)
+2X,
![](http://thumb.1010pic.com/pic5/latex/602.png)
-
![](http://thumb.1010pic.com/pic5/latex/96.png)
=
![](http://thumb.1010pic.com/pic5/latex/96.png)
+2X-
![](http://thumb.1010pic.com/pic5/latex/96.png)
,
![](http://thumb.1010pic.com/pic5/latex/42997.png)
÷2=2X÷2,
X=
![](http://thumb.1010pic.com/pic5/latex/45758.png)
;
(2)x+1.5x=30,
2.5x=30,
2.5x÷2.5=30÷2.5,
x=12;
(3)2x÷5=15,
2x÷5×5=15×5,
2x÷2=75÷2,
x=37.5.
分析:(1)根据等式的性质,在方程两边同时加2X,再减去
![](http://thumb.1010pic.com/pic5/latex/96.png)
,最后除以2求解,
(2)先化简,再根据等式的性质,在方程两边同时除以2.5求解,
(3)根据等式的性质,在方程两边同时乘5,再除以2求解.
点评:本题考查了学生根据等式的性质解方程的能力,注意等号对齐.