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\begin{document}
\begin{equation*}
    \frac{dx}{dt} = \begin{bmatrix} 0 & \dfrac{R_4}{R_1R_3C_1} \\[2ex]
      -\dfrac{1}{R_2 C_2} & 0
    \end{bmatrix} x
\end{equation*}
\end{document}