\(a,\\ \left\{{}\begin{matrix}x< 1.hoặc.x>2\\\dfrac{2x^2-3x-2}{3x+1}\le0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< 1.hoặc.x>2\\x\le\dfrac{-1}{2}.hoặc.\dfrac{-1}{3}< x< 1\end{matrix}\right.\\ \Rightarrow x\le-\dfrac{1}{2}.hoặc.-\dfrac{1}{3}< x< 1\)
\(b,\\ \left\{{}\begin{matrix}x< -4.hoặc.x>1\\\dfrac{2x+1}{2x^2-5x+2}\le0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x< -4.hoặc.x>1\\x\le-\dfrac{1}{2}hoặc.\dfrac{1}{2}< x< 2\end{matrix}\right.\\ \Rightarrow x< -4.hoặc.1< x< 2\)