\[ (a+x y(x)) y'(x)+b y(x)=0 \] ✓ Mathematica : cpu = 0.0755633 (sec), leaf count = 40
\[\text {Solve}\left [x=c_1 e^{-\frac {y(x)}{b}}-\frac {a e^{-\frac {y(x)}{b}} \text {Ei}\left (\frac {y(x)}{b}\right )}{b},y(x)\right ]\] ✓ Maple : cpu = 0.059 (sec), leaf count = 30
\[ \left \{ {\it \_C1}+ \left ( -{{\rm e}^{{\frac {y \left ( x \right ) }{b}}}}bx+a{\it Ei} \left ( 1,-{\frac {y \left ( x \right ) }{b}} \right ) \right ) ^{-1}=0 \right \} \]