Answer
$x=3, 1\pm\sqrt 2$; see graph.
Work Step by Step
Step 1. List possible rational zeros: $\frac{p}{q}=\pm1,\pm3$
Step 2. Test with synthetic division to find a zero at $x=3$, as shown in the figure.
Step 3. The function becomes:
$f(x)=-(x-3)(x^2-2x-1)$
Thus the zeros are $x=3, 1\pm\sqrt 2$
Step 4. Graph the function as shown in the figure.
