TeX Quellcode:
\begin{array}{rclcl} f_3(x_s) &=& f_4(x_s) \cr\dfrac{27}{9}x_s+1 &=& -\dfrac{21}{3}x_s-\dfrac{24}{4} \cr 3x_s+1 &=& -7x_s-6 &\vert & -1 \cr 3x_s &=& -7x_s-7 &\vert & +7x_s \cr 10x_s &=& -7 &\vert & :10 \cr x_s &=& -\dfrac{7}{10} \end{array}