TeX source:
\begin{array}{rclcl}z_1 = x^2 &=& \dfrac{4}{3} &\vert& \pm\sqrt{} \\x_{1,2} &=& \pm\sqrt{\dfrac{4}{3}} \\ x_{1,2} &=& \pm\dfrac{2\cdot\sqrt{3}}{3} \approx \pm 1{,}15 \\\\z_2 = x^2 &=& -4 &\vert& \pm\sqrt{} \\x_{3,4} &=& \pm\sqrt{-4}\end{array}