\frac{dx_{1}}{dt} = \left(1 \cdot k_{28} \cdot k_{19} + -1 \cdot k_{28} \cdot \left(k_{1} + k_{17} \cdot 2 \cdot x_{3} \cdot k_{10} / x_{1} / \left(k_{8} - x_{3} + k_{8} \cdot k_{9} / x_{1} + x_{3} \cdot k_{10} / x_{1} + k_{8} - x_{3} + k_{8} \cdot k_{9} / x_{1} + x_{3} \cdot k_{10} / x_{1}^{2} - 4 \cdot x_{3} \cdot k_{10} / x_{1} \cdot \left(k_{8} - x_{3}\right)^{\frac{1}{2}}\right)\right) \cdot x_{1}\right) / k_{28}\\
\frac{dx_{3}}{dt} = \left(1 \cdot \left(k_{4} + k_{18} \cdot x_{1} + k_{20} \cdot x_{3}^{k_{6}} / \left(k_{5}^{k_{6}} + x_{3}^{k_{6}}\right)\right) + -1 \cdot k_{27} \cdot k_{2} \cdot \left(1 + x_{2}\right) \cdot x_{3}\right) / k_{27}