TeX Quellcode:
\begin{array}{rclll}0{,}2a-0{,}3-0{,}5a+3{,}1a+0{,}7a &=& 1{,}9a+5-0{,}4a+2{,}7 \cr 3{,}5a-0{,}3 &=& 1{,}5a+7{,}7 & \vert & +0{,}3-1{,}5a \cr 3{,}5a-1{,}5a &=& 7{,}7+0{,}3 \cr 2a &=& 8 & \vert & : 2 \cr a &=& 4 \end{array}