Let $$f(x) = 2 x^4 (x - 6)^2.$$
(A) Use interval notation to indicate where $f(x)$ is increasing.
Note: Use 'INF' for $\infty$, '-INF' for $-\infty$, and use 'U' for the union symbol.
Increasing:

(B) Use interval notation to indicate where $f(x)$ is decreasing.

Decreasing:

(C) Find the average of the $x$ values of all local maxima of $f$.
Note: If there are no local maxima, enter -1000.

Average of $x$ values =

(D) Find the average of the $x$ values of all local minima of $f$.
Note: If there are no local minima, enter -1000.

Average of $x$ values =