The <span>possible numbers of real roots for a cubic function are 1 and 3. This is because they can be the roots of cubic function because most of the odd numbers are roots for cubic function. </span>
A cubic equation has degree 3. That means that the highest exponent of x (or whatever variable is being used) is 3. This means the function can have 0, 1, 2 or 3 roots.
Whatever the highest exponent of the variable is tells us the highest number of roots it can have. It can have that many or fewer but no less than 0.