\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) =-2\,{\frac {a}{-y \left( x \right) -2\,a-2\,a \left( y \left( x \right)  \right) ^{4}+16\,{a}^{2}x \left( y \left( x \right)  \right) ^{2}-32\,{a}^{3}{x}^{2}-2\,a \left( y \left( x \right)  \right) ^{6}+24\, \left( y \left( x \right)  \right) ^{4}{a}^{2}x-96\, \left( y \left( x \right)  \right) ^{2}{a}^{3}{x}^{2}+128\,{a}^{4}{x}^{3}}}=0}
\]