\[ \boxed { a{x}^{3} \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) +b \left ( y \left ( x \right ) \right ) ^{2}=0} \]
Mathematica: cpu = 90.744523 (sec), leaf count = 26 \[ \text {DSolve}\left [a x^3 y'(x) y''(x)+b y(x)^2=0,y(x),x\right ] \]
Maple: cpu = 0.047 (sec), leaf count = 42 \[ \left \{ y \left ( x \right ) ={{\rm e}^{\int ^{\ln \left ( x \right ) } \!{\it RootOf} \left ( -\int ^{{\it \_Z}}\!{\frac {a{\it \_a}}{a{{\it \_a}}^{3}-{{\it \_a}}^{2}a+b}}{d{\it \_a}}-{\it \_b}+{\it \_C1} \right ) {d{\it \_b}}+{\it \_C2}}} \right \} \]