TeX Quellcode:

\begin{array}{rclcll}0 &=& 2x^2+ax-1 &\vert& :2 \cr0 &=& x^2+\dfrac{a}{2}x-\dfrac12 &\vert& \text{p-q-Formel} \cr x_{1,2} &=& -\dfrac{a}{4}\pm\sqrt{\left(\dfrac{a}{4}\right)^2+\dfrac12} \cr x_{1,2} &=& -\dfrac{a}{4}\pm\sqrt{\dfrac{a^2}{16}+\dfrac{8}{16}} \cr x_{1,2} &=& -\dfrac{a}{4}\pm\sqrt{\dfrac{a^2+8}{16}} \cr x_{1,2} &=& \dfrac{-a\pm\sqrt{a^2+8}}{4}\end{array}