Consider the function $f(x)=-2x^3+33x^2-108x+4.$ For this function there are three important open intervals: $(-,A),(A,B),$ and $(B,)$ where A and $B$ are the critical numbers.

Find $A$

and $B$

For each of the following open intervals, tell whether $f(x)$ is increasing or decreasing.

$(-,A)$ : Decreasing $$

$(A,B)$:$1,,{}^6$

$(B,)$: Decreasing $v^{vv}{o}^b$