$x\in i,1,-i,-1,e^{\frac{\pi i}{3}},e^{\frac{5\pi i}{6}},e^{\frac{4\pi i}{3}},e^{\frac{11\pi i}{6}},e^{\frac{\pi i}{6}},e^{\frac{2\pi i}{3}},e^{\frac{7\pi i}{6}},e^{\frac{5\pi i}{3}}$

$x=1$
$x=-1$