Given the function $f(x) = 3x^{3}+18x^{2}-108x-5$.

It is decreasing on the interval(s): .

It is increasing on the interval(s): .

The function has a local maximum at $x =$ .

Enter $\infty$ and $-\infty$ as 'INF' and '-INF' respectively, and a union of intervals by entering "U".
    E.g. to represent $(-\infty, 1) \cup (3,5) \cup (7,\infty)$, enter: (-INF, 1) U (3, 5) U (7, INF).