Determine the total number of roots of each polynomial function using the factored form.

f (x) = (x + 1)(x - 3)(x - 4)
3

f (x) = (x - 6)2(x + 2)2
4

f (x) = (x + 5)3(x - 9)(x + 1)
5

f (x) = (x + 2)(x - 1)[x - (4 + 3i)][x - (4 - 3i)]
4