\[ f\left (a y(x)^2+x^2\right ) \left (a y(x) y'(x)+x\right )-x y'(x)-y(x)=0 \] ✗ Mathematica : cpu = 299.999 (sec), leaf count = 0 , timed out
$Aborted
✓ Maple : cpu = 0.377 (sec), leaf count = 45
\[ \left \{ -{ax \left ( y \left ( x \right ) \right ) ^{2}{\frac {1}{\sqrt {{a}^{2} \left ( y \left ( x \right ) \right ) ^{2}}}}}-\int ^{-{\frac {a \left ( y \left ( x \right ) \right ) ^{2}}{2}}-{\frac {{x}^{2}}{2}}}\!f \left ( -2\,{\it \_a} \right ) {d{\it \_a}}+{\it \_C1}=0 \right \} \]