TeX Quellcode:

\begin{array}{rclcl}0 &=& \dfrac{\log_{12}\left(\dfrac{5}{4}x\right)\cdot\ln(7)}{\ln(2x)} &\vert & \cdot\ln(2x) \\\\0 &=&\log_{12}\left(\dfrac{5}{4}x\right)\cdot\ln(7) &\vert& :\ln(7) \\\\0 &=& \log_{12}\left(\dfrac{5}{4}x\right) &\vert & 12^* \\\\1 &=& \dfrac{5}{4}x &\vert & : \dfrac{5}{4} \\\\x &=& \dfrac{4}{5} \in \mathbb{D}\end{array}