TeX source:

\text { (2) }(\mathrm{min} \text {. of f on }[3,5])=4 \leq \int_{3}^{5} \mathrm{f}(x) \mathrm{dx} \leq 2(\max \text {. of } \mathrm{f} \text { on }[3,5])=12 \text {. }