\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) ={\frac {{a}^{3}+ \left( y \left( x \right)  \right) ^{2}{a}^{3}+2\,y \left( x \right) {a}^{2}bx+a{b}^{2}{x}^{2}+ \left( y \left( x \right)  \right) ^{3}{a}^{3}+3\, \left( y \left( x \right)  \right) ^{2}{a}^{2}bx+3\,y \left( x \right) a{b}^{2}{x}^{2}+{b}^{3}{x}^{3}}{{a}^{3}}}=0}
\]