Tina owns a store that sells computers. Her profit, in dollars, is represented by the function P(x) =x3-20x2-96x, where x is the number of computers sold. Tina states that there are three possible values of x for which she will have a profit of $0. Find the values of x that produce a zero profit.
a x = 0
b x = -24
c x = 24
d x = 4
e x = -4