TeX Quellcode:

\begin{array}{rclll}\dfrac{x^2-x-12}{x^2-2x-15} &=& 0 &\vert& \cdot\left(x^2-2x-15\right) \cr x^2-x-12 &=& 0 &\vert& \text{p-q-Formel} \cr x_{1,2} &=& \dfrac{1}{2}\pm\sqrt{\left(\dfrac{1}{2}\right)^2+12} \cr x_{1,2} &=& \dfrac{1}{2}\pm\sqrt{\dfrac{49}{4}} \cr\cr x_1 &=& \dfrac{1}{2}+\dfrac{7}{2} = 4 \in\mathbb{D} \cr x_2 &=& \dfrac{1}{2}-\dfrac{7}{2} = -3 \not\in\mathbb{D} \end{array}