\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) ={\frac {-4\,xy \left( x \right) +{x}^{3}+2\,{x}^{2}-4\,x-8}{-8\,y \left( x \right) +2\,{x}^{2}+4\,x-8}}=0}
\]