In terms of the fundamental theorem, equal (repeating) roots are counted individually, even when you graph them they appear to be a single root. You have to consider the factors:
x^3(ax^2 + bx + c)
If x^3 = 0, this is the same thing as x * x * x = 0, or x = 0, x = 0, x = 0. Even though they are equal and repeating, they are still 3 factors of x in the original polynomial, and can be counted 3 times.
I hope this makes sense.