TeX source:
\begin{array}{rclll}8 &=& 2^{5a-3} &\vert & \log_2()\cr 3 &=& 5a-3 &\vert & +3\cr 6 &=& 5a &\vert & :5\cr a &=& \dfrac{6}{5} \in\mathbb{D} & & \rightarrow \quad P_2\left(\dfrac{6}{5} \mid 8\right)\end{array}