Question 4: Let $\mathrm{A}=[-2,4), \mathrm{B}=\left\{\mathrm{x} \mid \mathrm{x}^{2}-\mathrm{ax}-4 \leq 0\right\}$, if $\mathrm{B} \subseteq \mathrm{A}$, then the range of the real number $\mathrm{a}$ is $\qquad$ -
Question 4, Answer: Let $f(x)=x^{2}-a x-4$, then $B \subseteq A \Leftrightarrow\left\{\begin{array}{c}f(-2) \geq 0 \\ f(4)>0\end{array} \Leftrightarrow 0 \leq a<3\right.$, hence the range of values for $\mathrm{a}$ is $[0,3)$.