\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) + \left ( 4\,{a}^{2}x+3\,a{x}^{2}+b \right ) \left ( y \left ( x \right ) \right ) ^{3}+3\,x \left ( y \left ( x \right ) \right ) ^{2}=0} \]
Mathematica: cpu = 8.685603 (sec), leaf count = 490 \[ \text {Solve}\left [c_1=-\frac {i \sqrt {-\frac {4 a^3-3 b}{4 a^3}-\frac {3}{2 a^2 y(x)}+\frac {(-2 a-3 x)^2}{4 a^2}} J_{\frac {1}{2} \sqrt {\frac {4 a^3-3 b}{a^3}}+1}\left (-i \sqrt {\frac {(-2 a-3 x)^2}{4 a^2}-\frac {4 a^3-3 b}{4 a^3}-\frac {3}{2 a^2 y(x)}}\right )+\left (\frac {1}{2} \sqrt {\frac {4 a^3-3 b}{a^3}}+\frac {-2 a-3 x}{2 a}\right ) J_{\frac {1}{2} \sqrt {\frac {4 a^3-3 b}{a^3}}}\left (-i \sqrt {\frac {(-2 a-3 x)^2}{4 a^2}-\frac {4 a^3-3 b}{4 a^3}-\frac {3}{2 a^2 y(x)}}\right )}{i \sqrt {-\frac {4 a^3-3 b}{4 a^3}-\frac {3}{2 a^2 y(x)}+\frac {(-2 a-3 x)^2}{4 a^2}} Y_{\frac {1}{2} \sqrt {\frac {4 a^3-3 b}{a^3}}+1}\left (-i \sqrt {\frac {(-2 a-3 x)^2}{4 a^2}-\frac {4 a^3-3 b}{4 a^3}-\frac {3}{2 a^2 y(x)}}\right )+\left (\frac {1}{2} \sqrt {\frac {4 a^3-3 b}{a^3}}+\frac {-2 a-3 x}{2 a}\right ) Y_{\frac {1}{2} \sqrt {\frac {4 a^3-3 b}{a^3}}}\left (-i \sqrt {\frac {(-2 a-3 x)^2}{4 a^2}-\frac {4 a^3-3 b}{4 a^3}-\frac {3}{2 a^2 y(x)}}\right )},y(x)\right ] \]
Maple: cpu = 1.263 (sec), leaf count = 384 \[ \left \{ {\it \_C1}+{1 \left ( - \left ( {\frac {1}{2}\sqrt {{\frac {4\, {a}^{3}-3\,b}{{a}^{3}}}}}-{\frac {2\,a+3\,x}{2\,a}} \right ) {{\sl K}_{ {\frac {1}{2}\sqrt {{\frac {4\,{a}^{3}-3\,b}{{a}^{3}}}}}}\left (-{ \frac {\sqrt {3}}{2}\sqrt {{\frac {4\,y \left ( x \right ) {a}^{2}x+3\,a {x}^{2}y \left ( x \right ) +by \left ( x \right ) -2\,a}{{a}^{3}y \left ( x \right ) }}}}\right )}-{\frac {\sqrt {3}}{2}{{\sl K}_{{\frac {1}{2} \sqrt {{\frac {4\,{a}^{3}-3\,b}{{a}^{3}}}}}+1}\left (-{\frac {\sqrt {3} }{2}\sqrt {{\frac {4\,y \left ( x \right ) {a}^{2}x+3\,a{x}^{2}y \left ( x \right ) +by \left ( x \right ) -2\,a}{{a}^{3}y \left ( x \right ) }}}} \right )}\sqrt {{\frac {4\,y \left ( x \right ) {a}^{2}x+3\,a{x}^{2}y \left ( x \right ) +by \left ( x \right ) -2\,a}{{a}^{3}y \left ( x \right ) }}}} \right ) \left ( - \left ( {\frac {1}{2}\sqrt {{\frac {4\, {a}^{3}-3\,b}{{a}^{3}}}}}-{\frac {2\,a+3\,x}{2\,a}} \right ) {{\sl I}_{ {\frac {1}{2}\sqrt {{\frac {4\,{a}^{3}-3\,b}{{a}^{3}}}}}}\left (-{ \frac {\sqrt {3}}{2}\sqrt {{\frac {4\,y \left ( x \right ) {a}^{2}x+3\,a {x}^{2}y \left ( x \right ) +by \left ( x \right ) -2\,a}{{a}^{3}y \left ( x \right ) }}}}\right )}+{\frac {\sqrt {3}}{2}{{\sl I}_{{\frac {1}{2} \sqrt {{\frac {4\,{a}^{3}-3\,b}{{a}^{3}}}}}+1}\left (-{\frac {\sqrt {3} }{2}\sqrt {{\frac {4\,y \left ( x \right ) {a}^{2}x+3\,a{x}^{2}y \left ( x \right ) +by \left ( x \right ) -2\,a}{{a}^{3}y \left ( x \right ) }}}} \right )}\sqrt {{\frac {4\,y \left ( x \right ) {a}^{2}x+3\,a{x}^{2}y \left ( x \right ) +by \left ( x \right ) -2\,a}{{a}^{3}y \left ( x \right ) }}}} \right ) ^{-1}}=0 \right \} \]
Sage: cpu = 0 (sec), leaf count = 0 \[ \text {Maxima was unable to solve this ODE} \]