3 roots, since the polynomial is of third degree.
This follows immediately from the zero product property: if

, then either

or

. We have

from which it follows that

each of which admits only one solution.
Or, using the fundamental theorem of algebra, expanding we have a polynomial that is of third degree:

The theorem states that a polynomial

will have up to

distinct roots. In this case, it follows that there are exactly 3, since the solutions to the system above are all distinct.