Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
\frac{{x - 4m}}{{2 - x}} > 0\,\,\,\,\,\,\left( {x \ne 2} \right)\\
\Leftrightarrow \frac{{x - 4m}}{{x - 2}} < 0\\
\Leftrightarrow \left\{ \begin{array}{l}
\left( {x - 4m} \right)\left( {x - 2} \right) < 0\\
x \ne 2
\end{array} \right.\,\,\,\,\,\,\,\left( * \right)\\
TH1:4m < 2 \Leftrightarrow m < \frac{1}{2}\\
\left( * \right) \Leftrightarrow \left\{ \begin{array}{l}
4m < x < 2\\
x \ne 2
\end{array} \right. \Rightarrow S = \left( {4m;2} \right)\\
TH2:\,\,\,4m \ge 2 \Leftrightarrow m \ge \frac{1}{2}\\
\left( * \right) \Leftrightarrow \left\{ \begin{array}{l}
2 < x < 4m\\
x \ne 2
\end{array} \right. \Rightarrow S = \left( {2;4m} \right)
\end{array}\)
