Question

Is `f(x)=(x-3)(x+3)(x-2)` increasing or decreasing at `x=3`?

Answer 1

Increasing.

Explanation:

Expand `f(x)` to get `x^3-2x^2-9x+18`
Differentiate to get
`3x^2-4x-9`
Insert `x=3` and you get `df(x)/dx=6`

You have a positive value. Positive derivatives means increasing values.