1 câu trả lời
$\begin{array}{l} \left( {m - 7;m} \right) \subset \left( { - 4;3} \right)\\ \Rightarrow \left\{ \begin{array}{l} m - 7 \ge - 4\\ m \le 3 \end{array} \right. \Rightarrow \left\{ \begin{array}{l} m \ge - 4 + 7\\ m \le 3 \end{array} \right. \Rightarrow \left\{ \begin{array}{l} m \ge 3\\ m \le 3 \end{array} \right. \Rightarrow m = 3 \end{array}$
