\[
\boxed{
9\, \left( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right)  \right) ^{2}{\frac {{\rm d}^{5}}{{\rm d}{x}^{5}}}y \left( x \right) -45\, \left( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right)  \right)  \left( {\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left( x \right)  \right) {\it d4y} \left( x \right) +40\,{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left( x \right) =0}
\]