Find the interval(s) on which $f(x) = 2 x^{3} - 24 x + 5$ is strictly decreasing.

Explanation

1. 01

   $f'(x) = 6 \left(x - 2\right) \left(x + 2\right)$, which is 0 at $x = -2, 2$.

2. 02

   $f'(x) > 0$ on $(-\infty, -2) \cup (2, \infty)$ and $f'(x) < 0$ on $(-2, 2)$.

3. 03

   So $f$ is strictly decreasing on $(-2, 2)$.