Giải thích các bước giải:
\(\begin{array}{l}
a.\left( {m + 2} \right){x^2} - 2\left( {m + 2} \right)x + m + 1 < 0\\
\Leftrightarrow \left\{ \begin{array}{l}
m + 2 < 0\\
{m^2} + 4m + 4 - \left( {m + 2} \right)\left( {m + 1} \right) < 0
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
m < - 2\\
{m^2} + 4m + 4 - {m^2} - 3m - 2 < 0
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
m < - 2\\
m < - 2
\end{array} \right.\\
\to m < - 2\\
b.\left( {m - 1} \right){x^2} - 2\left( {m - 1} \right)x + m - 3 \ge 0\\
\Leftrightarrow \left\{ \begin{array}{l}
m \ge 1\\
{m^2} - 2m + 1 - \left( {m - 1} \right)\left( {m - 3} \right) \le 0
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
m \ge 1\\
{m^2} - 2m + 1 - {m^2} + 4m - 3 \le 0
\end{array} \right.\\
\Leftrightarrow \left\{ \begin{array}{l}
m \ge 1\\
m \le 1
\end{array} \right.\\
\to m = 1
\end{array}\)
