Answer
$\{-\frac{1}{2}, 1, 2 \}$
Work Step by Step
Step 1. List all possible rational zeros:
$\frac{p}{q}=\pm1,\pm2,\pm\frac{1}{2}$
Step 2. Use synthetic division as shown in the figure to get a zero at $x=1$ and the function as
$f(x)=(x-1)(2x^2-3x-2)=(x-1)(x-2)(2x+1)$
Step 3. The zeros are $\{-\frac{1}{2}, 1, 2 \}$
