Since we have three roots we can safely assume that our polynomial is a cubic function.
We can right cubic function as p(x)=ax3+bx2+cx+d with constants, or p(x)=(x-a)(x-b)(x-c) where a, b, and c are the roots or zeros of p(x).
So using this to your problem you get that p(x)=(x+13)(x-0)(x-2)=(x2+13x)(x-2)=x3+11x2-26x