In Exercises 39 through 42, the second derivative f"(x) of a function is given. In each case, use this information to determine where the graph of f(x) is concave upward and concave downward and find all values of x for which an inflection point occurs. [You are not required to find f(x) or the y coordinates of the inflection points.]

f"(x) = x³(x² + 2x − 3)