\[
\boxed{
x \left( a{\frac {\rm d}{{\rm d}x}}y \left( x \right) +b{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) +c{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left( x \right) +e{\it d4y} \left( x \right)  \right) y \left( x \right) =0}
\]