Answer:
relative minimum
Explanation:
From f^''(x) = 12x we can take the integration to find out what f'(x) is:

Furthermore, we can substitute x = 1 for f''(x) to find out whether it's positive or negative
f''(1) = 12*1 = 12 > 0
So if x=1 is a critical point of f'(x) and f''(x=1) > 0 then that point is a relative minimum point