TeX Quellcode:
\begin{array}{rclll}\dfrac{(x^2+x-2)^2}{x^4+2x^2-8} &=& 0 &\vert& \cdot \left(x^4+2x^2-8\right)\cr (x^2+x-2)^2 &=& 0 &\vert& \pm\sqrt{} \cr x^2+x-2 &=& 0 &\vert& \text{a-b-c-Formel} \cr x_{1,2} &=& \dfrac{-1\pm\sqrt{1+8}}{2} \cr\cr x_{1} &=& 1 \in\mathbb{D} \cr x_{2} &=& -2 \in\mathbb{D} \end{array}