Determine the different possibilities for the numbers of positive, negative, and nonreal complex zeros for the following function.
f(x) = 4x^3 - 5x^2 + 4x + 9
What is the possible number of positive real zeros of this function?
(Use a comma to separate answers as needed.)
What is the possible number of negative real zeros of this function?
(Use a comma to separate answers as needed.)
What is the possible number of nonreal complex zeros?
(Use a comma to separate answers as needed.)