\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) ={\frac {y \left( x \right) }{x \left( -1+y \left( x \right) +{x}^{2} \left( y \left( x \right)  \right) ^{3}+ \left( y \left( x \right)  \right) ^{4}{x}^{3} \right) }}=0}
\]