<exercise masterit-seed="7815" masterit-slug="C3" masterit-name="Homogeneous second-order linear ODE">
<statement>
<p>Explain how to find the general solution to each given ODE using
exponential functions.</p>
<p>For each exponential solution using complex numbers, also provide
an alternate general solution using only real numbers.</p>
<ol>
<li>
<me> 18 \, {y'} = 27 \, {y} + 3 \, {y''} </me>
</li>
<li>
<me> -102 \, {x} - 3 \, {x''} - 18 \, {x'} = 0 </me>
</li>
</ol>
</statement>
<answer>
<me> {x} = c_{1} e^{\left(\left(5 i - 3\right) \, t\right)} + c_{2} e^{\left(-\left(5 i + 3\right) \, t\right)} </me>
<me> {x} = {\left(d_{1} \cos\left(5 \, t\right) + d_{2} \sin\left(5 \, t\right)\right)} e^{\left(-3 \, t\right)} </me>
<me> {y} = k_{1} t e^{\left(3 \, t\right)} + k_{2} e^{\left(3 \, t\right)} </me>
</answer>
</exercise>