\[ \boxed { \ln \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) +a \left ( x{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -y \left ( x \right ) \right ) =0} \]
Mathematica: cpu = 0.042005 (sec), leaf count = 28 \[ \left \{\left \{y(x)\to -\frac {e^{-c_1} \left (e^{c_1} c_1-a x\right )}{a}\right \}\right \} \]
Maple: cpu = 0.031 (sec), leaf count = 36 \[ \left \{ y \left ( x \right ) ={\it \_C1}\,x+{\frac {\ln \left ( {\it \_C1} \right ) }{a}},y \left ( x \right ) ={\frac {1}{a}\ln \left ( -{ \frac {1}{ax}} \right ) }-{a}^{-1} \right \} \]