How to complete the following table?

And also:

a) f(x) = 2x^3 + 3x^2 - 12x + 6 has critical points atx= -2 andx= 1. Use the second derivative test to determine whether these are local maximum or local minimum values.

b) how to Calculate f(-2) and f(1) . Briefly explain the appropriateness of these two values