If $\displaystyle P(x)$ has remainder $\displaystyle 2$ when divided by $\displaystyle (x-3)$ and remainder $\displaystyle -13$ when divided by $\displaystyle (x+2)$, find the remainder when $\displaystyle P(x)$ is divided by $\displaystyle (x^2 - x - 6)$

I know that $\displaystyle P(k)=Q(k)(k-k)+R =R$

Please, I need help for this one!