TeX Quellcode:

\begin{array}{crclllcc} \text{I} & 52a+156y &=& -104 & \vert : 13 \cr \text{II} & -4a-12y &=& 8 \cr \cr \text{I} & 4a+12y &=& -8 \cr \text{II} & -4a-12y &=& 8 \cr \cr \text{I} & 4a+12y &=& -8 \cr \text{I+II} & 0a+0y &=& 0 \end{array}