TeX Quellcode:

\begin{array}{rclll} 27 &=& \dfrac{\sqrt{x^2-9}}{4}-3 &\vert& +3 \cr 30 &=& \dfrac{\sqrt{x^2-9}}{4} &\vert& \cdot 4 \cr 120 &=& \sqrt{x^2-9} &\vert& ()^2 \cr 14.400 &=& x^2-9 &\vert& +9 \cr 14.409 &=& x^2 &\vert &\pm\sqrt{} \cr\cr x_1 &=& \sqrt{14.409}\approx 120{,}04 \in\mathbb{D}\cr x_2 &=& -\sqrt{14.409}\approx -120{,}04\in\mathbb{D} \end{array}