\[ y'(x)=\frac {-\exp \left (\frac {2 (x-y(x))^3 (y(x)+x)^3}{x^2-y(x)^2-1}\right )-x^2-2 x y(x)-y(x)^2}{\exp \left (\frac {2 (x-y(x))^3 (y(x)+x)^3}{x^2-y(x)^2-1}\right )-x^2-2 x y(x)-y(x)^2} \] ✗ Mathematica : cpu = 300.004 (sec), leaf count = 0 , timed out
$Aborted
✓ Maple : cpu = 0.663 (sec), leaf count = 43
\[ \left \{ y \left ( x \right ) ={{\rm e}^{{\it RootOf} \left ( -{\it \_Z}+\int ^{ \left ( {{\rm e}^{{\it \_Z}}} \right ) ^{2}-2\,{{\rm e}^{{\it \_Z}}}x}\! \left ( {{\rm e}^{2\,{\frac {{{\it \_a}}^{3}}{{\it \_a}+1}}}}+{\it \_a} \right ) ^{-1}{d{\it \_a}}+{\it \_C1} \right ) }}-x \right \} \]