x=0\qquad 0=-3\cdot f(0)\implies f(0)=0\implies x\mid f(x)\\x=3\qquad 3\cdot f(2)=0\implies f(2)=0\implies (x-2)\mid f(x)\\x=1\qquad \underbrace{1\cdot f(0)}_{=0}=-2f(1)\implies f(1)=0\implies (x-1)\mid f(x)