\[ y'(x)=\frac {x^2+2 x y(x)+e^{2 (x-y(x))^2 (y(x)+x)^2}+y(x)^2}{x^2+2 x y(x)-e^{2 (x-y(x))^2 (y(x)+x)^2}+y(x)^2} \] ✗ Mathematica : cpu = 300. (sec), leaf count = 0 , timed out
$Aborted
✓ Maple : cpu = 0.299 (sec), leaf count = 38
\[ \left \{ y \left ( x \right ) ={{\rm e}^{{\it RootOf} \left ( -{\it \_Z}+\int ^{ \left ( {{\rm e}^{{\it \_Z}}} \right ) ^{2}-2\,{{\rm e}^{{\it \_Z}}}x}\! \left ( {{\rm e}^{2\,{{\it \_a}}^{2}}}+{\it \_a} \right ) ^{-1}{d{\it \_a}}+{\it \_C1} \right ) }}-x \right \} \]