TeX source:
\begin{array}{rclcl} z_1 = x^2 &=& \dfrac13 &\vert& \pm\sqrt{} \cr\cr x_{3,4} &=& \pm\sqrt{\dfrac13} \cr\cr z_2 = x^2 &=& -\dfrac23 &\vert& \pm\sqrt{} \cr\cr x_{5,6} &=& \pm\sqrt{-\dfrac23}\end{array}