$$x_{3} = - \frac{5}{2} - \frac{5 \left(-5 - \sqrt{3} i\right)^{2}}{12} - \frac{5 \sqrt{3} i}{6} - \frac{\left(-5 - \sqrt{3} i\right)^{3}}{12}$$
=
$$-5 + \sqrt{3} i$$
=
-5 + 1.73205080756888*i
$$y_{3} = -5 - \sqrt{3} i$$
=
$$-5 - \sqrt{3} i$$
=
-5 - 1.73205080756888*i
$$x_{4} = - \frac{5}{2} - \frac{\left(-5 + \sqrt{3} i\right)^{3}}{12} + \frac{5 \sqrt{3} i}{6} - \frac{5 \left(-5 + \sqrt{3} i\right)^{2}}{12}$$
=
$$-5 - \sqrt{3} i$$
=
-5 - 1.73205080756888*i
$$y_{4} = -5 + \sqrt{3} i$$
=
$$-5 + \sqrt{3} i$$
=
-5 + 1.73205080756888*i