okay so i have been given a question of :

on the graph of $\displaystyle y = 2x^3 -9x^2 - 12x - 7$

, the point (1, -2) is:

a minimum , a max , neither but on the graph or not on the graph.

So i have never done this before. Do i differentiate the equation and substitute values of x? Or is it a different way?

Thanks People your help is appreciated.