TeX Quellcode:

\begin{array}{rcl}f\left(x_1\right) &=& f\left(6\right) \cr &=& 3\cdot 6 + 7 \cr &=& 25 \cr\cr f\left(x_2\right) &=& f\left(1\right) \cr &=& 3\cdot 1 + 7 \cr &=& 10 \end{array}