Lời giải:
Để \(B\subset A\) \(\left\{\begin{matrix} m+1\leq 1\\ m^2+2\geq 6\end{matrix}\right.\Leftrightarrow \left\{\begin{matrix} m\leq 0\\ m^2\geq 4\end{matrix}\right.\)
\(\Leftrightarrow \left\{\begin{matrix} m\leq 0\\ (m-2)(m+2)\geq 0\end{matrix}\right.\)
\(\Leftrightarrow m\leq -2\)