\frac{dx_{1}}{dt} = \left(1 \cdot k_{1} \cdot k_{2} + 1 \cdot k_{1} \cdot k_{3} \cdot x_{1} + -1 \cdot k_{1} \cdot k_{4} \cdot x_{2} \cdot x_{1} / \left(k_{5} + x_{1}\right) + -1 \cdot k_{1} \cdot k_{6} \cdot x_{3} \cdot x_{1} / \left(k_{7} + x_{1}\right)\right) / k_{1}\\
\frac{dx_{2}}{dt} = \left(1 \cdot k_{1} \cdot k_{8} \cdot x_{1} + -1 \cdot k_{1} \cdot k_{10} \cdot x_{2} / \left(k_{9} + x_{2}\right)\right) / k_{1}\\
\frac{dx_{3}}{dt} = \left(1 \cdot k_{1} \cdot k_{11} \cdot x_{1} + -1 \cdot k_{1} \cdot k_{13} \cdot x_{3} / \left(k_{12} + x_{3}\right)\right) / k_{1}