a Find the critical numbers off Enter your answers as a comm

(a) Find the critical numbers off. (Enter your answers as a comma-separated list.)
x=
(b) Find the open intervals on which the function is increasing or decreasing. (Select all that apply.)
Increasing:

Solution

df/dx=0 6x^2+6x-72=0 x^2+x-12=0 x=-4,3 b) df/dx>0 (x+4)(x-3)>0 x>3 or x<-4 (-infi,-4) (3,infi) c) rest region it is decreasing so (-4,3)