a/ \(\dfrac{x-2}{x+3}<0\\↔\begin{cases}x-2>0\\x+3<0\end{cases}\quad or\quad \begin{cases}x-2<0\\x+3>0\end{cases}\\↔\begin{cases}x>2\\x<-3\end{cases}\quad or\quad \begin{cases}x<2\\x>-3\end{cases}\\→2>x>-3\)
b/ \(\dfrac{2x-3}{5-x}≤0\\↔\begin{cases}2x-3≥0\\5-x<0\end{cases}\quad or\quad \begin{cases}2x-3≤0\\5-x>0\end{cases}\\↔\begin{cases}x≥\dfrac{3}{2}\\x>5\end{cases}\quad or\quad \begin{cases}x≤\dfrac{3}{2}\\x<5\end{cases}\\↔x>5\quad or\quad x≤\dfrac{3}{2}\)
