To convert the third order differential equation $\frac{d^3 u}{d t^3} + 3 \frac{d^2 u}{d t^2} + 4 \frac{d u}{d t} + 12 u = 0$ into a first order system, introduce new variables:
Let $v = \frac{du}{dt}$ and $w = \frac{dv}{dt}$. Then $\frac{du}{dt} = v$ and
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