TeX source:
\begin{array}{rclll} f\left(\dfrac{1}{3}\right) &=& \left\vert -2\cdot\left(\dfrac{1}{3}\right)^2-20\cdot\dfrac{1}{3}+78 \right\vert &=& \dfrac{640}{9} \quad \rightarrow \quad P_1\left(\dfrac{1}{3} \mid \dfrac{640}{9}\right) \end{array}