The derivative of continuous function `f` is given by

f'(x)=61x(64x2)31

create an interval table then determine which statements are true.

a)f has local max at x=-8

b)f is increasing on (-8,0) u (8,infinite)

c)x=0 is the only critical value

d)f has local min at x=8

e) f is decreasing on (-infinite, 0)