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