\[
\boxed{
 \left( {\frac {\rm d}{{\rm d}x}}y \left( x \right)  \right) ^{2}-3\,x \left( y \left( x \right)  \right) ^{2/3}{\frac {\rm d}{{\rm d}x}}y \left( x \right) +9\, \left( y \left( x \right)  \right) ^{5/3}=0}
\]