\[ y'(x)=\frac {-2 a x^2-x^3-4 x y(x)-4 x+8}{4 a x+2 x^2+8 y(x)+8} \] ✓ Mathematica : cpu = 0.0406884 (sec), leaf count = 45
DSolve[Derivative[1][y][x] == (8 - 4*x - 2*a*x^2 - x^3 - 4*x*y[x])/(8 + 4*a*x + 2*x^2 + 8*y[x]),y[x],x]
\[\left \{\left \{y(x)\to \frac {1}{4} \left (-2 a x-x^2-4\right )-\frac {2 \left (1+W\left (-e^{-\frac {a^2 x}{4}-1+c_1}\right )\right )}{a}\right \}\right \}\] ✓ Maple : cpu = 0.198 (sec), leaf count = 51
dsolve(diff(y(x),x) = (-4*x*y(x)-x^3-2*a*x^2-4*x+8)/(8*y(x)+2*x^2+4*a*x+8),y(x))
\[y \left (x \right ) = \frac {-2 a^{2} x -a \,x^{2}-8 \LambertW \left (-\frac {{\mathrm e}^{-\frac {a^{2} x}{4}} {\mathrm e}^{-\frac {a}{2}} {\mathrm e}^{-1} {\mathrm e}^{\frac {c_{1} a^{2}}{4}}}{2}\right )-4 a -8}{4 a}\]