\frac{dx_{1}}{dt} = \left(1 \cdot k_{11} \cdot \left(k_{1} \cdot k_{9} + k_{2} \cdot x_{1} \cdot x_{2} / \left(k_{3} + x_{2}\right)\right) + -1 \cdot k_{11} \cdot \left(k_{4} \cdot x_{1} \cdot x_{2} + k_{5} \cdot x_{1}\right)\right) / k_{11}\\
\frac{dx_{2}}{dt} = \left(1 \cdot k_{11} \cdot k_{6} \cdot x_{2} \cdot \left(1 - k_{7} \cdot x_{2}\right) + -1 \cdot k_{11} \cdot \left(k_{8} \cdot x_{1} \cdot x_{2} + k_{10} \cdot x_{2}\right)\right) / k_{11}