题目内容
解方程.
![]() ![]() | (1+![]() | 0.26×3-0.9x=6% |
解:(1)
:
=x:48,
x=
×48,
x÷
=
×48
,
x=10;
(2)(1+
)x=6.25,
x=6.25,
x÷
=6.25÷
,
x=3.75;
(3)0.26×3-0.9x=6%,
0.78-0.9x=6%,
0.78-0.9x+0.9x=6%+0.9x,
0.78=6%+0.9x,
0.78-6%=6%+0.9x-6%,
0.72=0.9x,
0.72÷0.9=0.9x÷0.9,
x=0.8.
分析:(1)根据比例的基本性质,把原式转化为
x=48×
,再根据等式的性质,在方程两边同时除以
求解,
(2)先化简方程,再根据等式的性质,在方程两边同时除以
求解,
(3)先化简方程,再根据等式的性质,方程两边加上0.9x,再同时减去6%,然后同时除以0.9求解.
点评:此题考查了解比例和解方程的能力,注意等号对齐.
![](http://thumb.1010pic.com/pic5/latex/7.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/7.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/7.png)
![](http://thumb.1010pic.com/pic5/latex/204651.png)
x=10;
(2)(1+
![](http://thumb.1010pic.com/pic5/latex/168.png)
![](http://thumb.1010pic.com/pic5/latex/1231.png)
![](http://thumb.1010pic.com/pic5/latex/1231.png)
![](http://thumb.1010pic.com/pic5/latex/1231.png)
![](http://thumb.1010pic.com/pic5/latex/1231.png)
x=3.75;
(3)0.26×3-0.9x=6%,
0.78-0.9x=6%,
0.78-0.9x+0.9x=6%+0.9x,
0.78=6%+0.9x,
0.78-6%=6%+0.9x-6%,
0.72=0.9x,
0.72÷0.9=0.9x÷0.9,
x=0.8.
分析:(1)根据比例的基本性质,把原式转化为
![](http://thumb.1010pic.com/pic5/latex/602.png)
![](http://thumb.1010pic.com/pic5/latex/7.png)
![](http://thumb.1010pic.com/pic5/latex/602.png)
(2)先化简方程,再根据等式的性质,在方程两边同时除以
![](http://thumb.1010pic.com/pic5/latex/304.png)
(3)先化简方程,再根据等式的性质,方程两边加上0.9x,再同时减去6%,然后同时除以0.9求解.
点评:此题考查了解比例和解方程的能力,注意等号对齐.
![](http://thumb2018.1010pic.com/images/loading.gif)
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