解:(1)
![](http://thumb.1010pic.com/pic5/latex/26485.png)
=
![](http://thumb.1010pic.com/pic5/latex/142804.png)
,
48x=36×20,
48x÷48=720÷48,
x=15;
(2)14.2-
![](http://thumb.1010pic.com/pic5/latex/335.png)
x=4.5,
14.2-
![](http://thumb.1010pic.com/pic5/latex/335.png)
x+
![](http://thumb.1010pic.com/pic5/latex/335.png)
x=4.5+
![](http://thumb.1010pic.com/pic5/latex/335.png)
x,
14.2=4.5+
![](http://thumb.1010pic.com/pic5/latex/335.png)
x,
14.2-4.5=4.5+
![](http://thumb.1010pic.com/pic5/latex/335.png)
x-4.5,
9.7=
![](http://thumb.1010pic.com/pic5/latex/335.png)
x,
9.7÷
![](http://thumb.1010pic.com/pic5/latex/335.png)
=
![](http://thumb.1010pic.com/pic5/latex/335.png)
x÷
![](http://thumb.1010pic.com/pic5/latex/335.png)
,
x=24.25;
(3)
![](http://thumb.1010pic.com/pic5/latex/1154.png)
:
![](http://thumb.1010pic.com/pic5/latex/35.png)
=
![](http://thumb.1010pic.com/pic5/latex/4458.png)
:x,
![](http://thumb.1010pic.com/pic5/latex/1154.png)
x=
![](http://thumb.1010pic.com/pic5/latex/35.png)
×
![](http://thumb.1010pic.com/pic5/latex/4458.png)
,
![](http://thumb.1010pic.com/pic5/latex/1154.png)
x÷
![](http://thumb.1010pic.com/pic5/latex/1154.png)
=
![](http://thumb.1010pic.com/pic5/latex/35.png)
×
![](http://thumb.1010pic.com/pic5/latex/4458.png)
![](http://thumb.1010pic.com/pic5/latex/202457.png)
,
x=
![](http://thumb.1010pic.com/pic5/latex/15509.png)
.
分析:(1)先化简方程,再根据等式的性质,在方程两边同时除以48求解,
(2)根据等式的性质,在方程两边同时加上
![](http://thumb.1010pic.com/pic5/latex/335.png)
x,再减去4.5.5,最后除以
![](http://thumb.1010pic.com/pic5/latex/335.png)
求解,
(3)先化简比例,再根据等式的性质,在方程两边同时除以
![](http://thumb.1010pic.com/pic5/latex/1154.png)
求解.
点评:本题考查了学生根据等式的性质和比例的基本性质解答方程的能力,注意等号对齐.