\[
\boxed{
2\, \left( {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right)  \right) y \left( x \right) - \left( {\frac {\rm d}{{\rm d}x}}y \left( x \right)  \right) ^{2}+3\,f \left( x \right) y \left( x \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) +2\, \left(  \left( f \left( x \right)  \right) ^{2}+{\frac {\rm d}{{\rm d}x}}f \left( x \right)  \right)  \left( y \left( x \right)  \right) ^{2}-8\, \left( y \left( x \right)  \right) ^{3}=0}
\]