Hello there!
The critical points are....
[tex](x,f(x)) = (-2, 0)
[/tex]
[tex](x,f(x))=(3,0)[/tex]
[tex](x,f(x))=( \frac{7}{9}, \frac{1562500000000}{387420489}) or (0.777777777777778,4033.08561205187)[/tex]
Therefore 3 is your answer!
Hope this helps!
