\[ y'(x)-x y(x)^2-3 x y(x)=0 \] ✓ Mathematica : cpu = 0.02218 (sec), leaf count = 39
\[\left \{\left \{y(x)\to -\frac {3 e^{3 c_1+\frac {3 x^2}{2}}}{e^{3 c_1+\frac {3 x^2}{2}}-1}\right \}\right \}\]
✓ Maple : cpu = 0.013 (sec), leaf count = 19
\[ \left \{ y \left ( x \right ) =3\, \left ( -1+3\,{{\rm e}^{-3/2\,{x}^{2}}}{\it \_C1} \right ) ^{-1} \right \} \]