7) \([\begin{matrix} \dot{x}_1 \\ \dot{x}_2 \end{matrix}] = [\begin{matrix} 0 & -1 \\ 1 & 0 \end{matrix}] [\begin{matrix} x_1 \\ x_2 \end{matrix}]\)
\(\dot{x}_1 = -x_2\)
\(\dot{x}_2=x_1\)
\(\frac{\dot{x}_1}{\dot{x}_2} = \frac{-x_2}{x_1}\)