\[ y'(x)=\frac {-2 a x^2-x^3-4 x y(x)-4 x+8}{4 a x+2 x^2+8 y(x)+8} \] ✓ Mathematica : cpu = 0.0267747 (sec), leaf count = 45
\[\left \{\left \{y(x)\to \frac {1}{4} \left (-2 a x-x^2-4\right )-\frac {2 \left (1+W\left (-e^{-\frac {a^2 x}{4}-1+c_1}\right )\right )}{a}\right \}\right \}\] ✓ Maple : cpu = 0.348 (sec), leaf count = 51
\[ \left \{ y \left ( x \right ) ={\frac {1}{4\,a} \left ( -2\,{a}^{2}x-a{x}^{2}-8\,{\it lambertW} \left ( -1/2\,{{\rm e}^{-1/4\,{a}^{2}x}}{{\rm e}^{-a/2}}{{\rm e}^{-1}}{{\rm e}^{1/4\,{\it \_C1}\,{a}^{2}}} \right ) -4\,a-8 \right ) } \right \} \]