x_{12} = \frac{472}{125} \cdot k_{1}\\
1 \cdot k_{13} \cdot x_{6} + 1 \cdot k_{13} \cdot x_{7} = k_{13} \cdot k_{14}\\
1 \cdot k_{13} \cdot x_{9} + 1 \cdot k_{13} \cdot x_{10} = k_{13} \cdot k_{15}