Answer
$\{-\frac{1}{5}, 3,\frac{-1\pm i\sqrt {7}}{2} \}$
Work Step by Step
1. List possible rational zeros: $\pm1, \pm2,\pm3,\pm6,\pm\frac{1}{5},\pm\frac{2}{5},\pm\frac{3}{5},\pm\frac{6}{5}$
2. Use synthetic division, we can find two zeros $-\frac{1}{5}, 3,$
3. Use the quotient to find the remaining zeros: $5x^2+5x+10=0$ or $x^2+x+2=0$, thus $x=\frac{-1\pm\sqrt {1-4(2)}}{2}=\frac{-1\pm i\sqrt {7}}{2}$
4. List all the solutions $\{-\frac{1}{5}, 3,\frac{-1\pm i\sqrt {7}}{2} \}$
