\[ \boxed { \left ( x{{\rm e}^{y \left ( x \right ) }}+{{\rm e}^{x}} \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +{{\rm e}^{y \left ( x \right ) }}+y \left ( x \right ) {{\rm e}^{x}}=0} \]
Mathematica: cpu = 0.049506 (sec), leaf count = 33 \[ \left \{\left \{y(x)\to c_1 e^{-x}-W\left (x e^{c_1 e^{-x}-x}\right )\right \}\right \} \]
Maple: cpu = 0.047 (sec), leaf count = 30 \[ \left \{ y \left ( x \right ) =-{\it lambertW} \left ( {\frac {x}{{ {\rm e}^{x}}} \left ( {{\rm e}^{{\frac {{\it \_C1}}{{{\rm e}^{x}}}}}} \right ) ^{-1}} \right ) -{\frac {{\it \_C1}}{{{\rm e}^{x}}}} \right \} \]