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dovanngochung123
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
a) 25 : (6-x)=5
b)2x: ( x+5).(2x+1).(x-6).(3x-9)=0
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b)2x: ( x+5).(2x+1).(x-6).(3x-9)=0
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