#### Answer

$f(x)=x^3-9x^2+27x-27$

#### Work Step by Step

RECALL:
If $a$ is a zero of a polynomial, then $x−a$ is a factor of the polynomial.
Thus, having $x=3, 3, 3$ as zeros of the polynomial function means that $x-3,x-3$, and $x-3$ are factors of the polynomial.
Therefore the function is
$f(x)=(x-3)(x-3)(x-3)
\\f(x)=x^3-9x^2+27x-27.$