\[
\boxed{
{\it d4y} \left( x \right) +6\,f{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left( x \right) + \left( 11\,{f}^{2}+4\,{\it df}+10\,g \right) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) + \left( 6\,{f}^{3}+7\,{\it df}\,f+30\,fg+{\it ddf}+10\,{\it dg} \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) +3\, \left( 6\,{f}^{2}g+2\,{\it df}\,g+5\,{\it dg}\,f+3\,{g}^{2}+{\it ddg} \right) y \left( x \right) =0}
\]