Answer
$y(x)=c_{1}e^{-3x}cos(5x)+c_{2}e^{-3x}sin(5x)$
Work Step by Step
First write the current derivatives as $y''$ etc., this is to make it easier. It is not obliged. After this you substitute the $y'', y'$ and $y$ with $y''=r^{2}e^{rx}, y'=re^{rx} and y=e^{rx}$. And by filling out the equation you can find the final equation.
