a/ \(\left\{{}\begin{matrix}m-2\ne0\\\Delta'=\left(2m-3\right)^2-\left(m-2\right)\left(5m-6\right)< 0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m\ne2\\-m^2+4m-3< 0\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m\ne2\\\left[{}\begin{matrix}m< 1\\m>3\end{matrix}\right.\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}m< 1\\m>3\end{matrix}\right.\)
b/ Để \(f\left(x\right)\le0\) có tập nghiệm R
\(\Leftrightarrow\left\{{}\begin{matrix}m-2< 0\\\Delta'=-m^2+4m-3\le0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}m< 2\\\left[{}\begin{matrix}m\le1\\m\ge3\end{matrix}\right.\end{matrix}\right.\) \(\Rightarrow m\le1\)
