Answer:
I got 1 when I solved this problem
Find the concavity changes of f(x).
Give the x-coordinates.
So, the answer to the multiple choice question is -1 and 5 since those points are where f''(x) changes sign.
Note: You can tell that you're supposed to find the concavity changes of f(x) and not f''(x) because from the graph it's obvious that the concavity of f"(x) doesn't change.
