~~~Học tốt~~~
Ta có: (x-0)(x-3)<0\(\Rightarrow\)\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x-0>0\\x-3< 0\end{matrix}\right.\\\left\{{}\begin{matrix}x-0< 0\\x-3>0\end{matrix}\right.\end{matrix}\right.\)\(\Rightarrow\)\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x>0\\x-3< 0\end{matrix}\right.\\\left\{{}\begin{matrix}0>x\\x-3>0\end{matrix}\right.\end{matrix}\right.\)\(\Rightarrow\)\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x>0\\x-3< 0\end{matrix}\right.\\x>x-3\left(vô\right)lí\end{matrix}\right.\)\(\Rightarrow\)\(\left\{{}\begin{matrix}x>0\\x-3< 0\end{matrix}\right.\)⇒0<x<3
Vậy x thõa mãn đề bài là 0<x<3
