Đáp án:
Giải thích các bước giải:
$\begin{array}{l}
B2:\\
Bpt \to \left\{ \begin{array}{l}
x \ge 2\\
{x^2} - 3x + 4 \le 4{x^2} - 16x + 16
\end{array} \right.\\
\to \left\{ \begin{array}{l}
x \ge 2\\
3{x^2} - 13x + 12 \ge 0
\end{array} \right. \to \left\{ \begin{array}{l}
x \ge 2\\
x \in \left( { - \infty ;\frac{4}{3}} \right) \cup \left( {3; + \infty } \right)
\end{array} \right.\\
KL:x \in \left( {3; + \infty } \right)\\
B3:\\
\left\{ \begin{array}{l}
- 4 < x < 1\\
x > m - 2
\end{array} \right.
\end{array}$
Để btp vô nghiệm
$\begin{array}{l}
\Leftrightarrow \left( {m - 2} \right) \in \left[ { - 4;1} \right]\\
\to \left\{ \begin{array}{l}
- 4 \le m - 2\\
m - 2 \le 1
\end{array} \right. \to \left\{ \begin{array}{l}
- 2 \le m\\
m \le 3
\end{array} \right. \to - 2 \le m \le 3
\end{array}$
