\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) -{\it a3}\, \left( y \left( x \right)  \right) ^{3}-{\it a2}\, \left( y \left( x \right)  \right) ^{2}-{\it a1}\,y \left( x \right) -{\it a0}=0}
\]