解:(1)3x+3×6
![](http://thumb.1010pic.com/pic5/latex/13.png)
=31.2,
3x+19.5=31.2,
3x+19.5-19.5=31.2-19.5,
3x=11.7,
3x÷3=11.7÷3,
x=3.9;
(2)7x-3
![](http://thumb.1010pic.com/pic5/latex/335.png)
x=0.72,
(7-3.4)x=0.72,
3.6x=0.72,
3.6x÷3.6=0.72÷3.6,
x=0.2.
分析:(1)先求出3×6
![](http://thumb.1010pic.com/pic5/latex/13.png)
=19.5,根据等式的性质,两边同减去19.5,再同除以3即可;
(2)运用乘法分配律改写成(7-3.4)x=0.72,即3.6x=0.72,再根据等式的性质,两边同除以3.6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、同减去或同除以、同乘上某一个数(0除外),等式的两边仍相等,同时注意等号上下要对齐.