#### Answer

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

#### Work Step by Step

RECALL:
If $a$ is a zero of a polynomial, then $x−a$ is a factor of the polynomial.
Thus, having $x=1, -1, -2$ as zeros of the polynomial function means that $x-1,x+1$, and $x+2$ are factors of the polynomial.
Therefore the function is
$f(x)=(x-1)(x+1)(x+2)
\\f(x)=x^3+2x^2-x-2.$