TeX Quellcode:

\begin{array}{rclcl}0 &=& \ln\left((x-81)^2\right) &\vert& e^{*} \cr 1 &=& (x-81)^2 &\vert & \pm\sqrt{} \cr \pm 1 &=& x-81 &\vert & +81 \cr \cr x_1 &=& 1+81 = 82\;\in\;\mathbb{D} \cr x_2 &=& -1+81 = 80\;\in\;\mathbb{D} \end{array}