\[ y'(x)=\frac {a^3 x^6}{64}+\frac {3}{32} a^2 b x^5+\frac {3}{16} a^2 x^4 y(x)+\frac {a^2 x^4}{16}+\frac {3}{16} a b^2 x^4+\frac {3}{4} a b x^3 y(x)+\frac {1}{4} a b x^3+\frac {3}{4} a x^2 y(x)^2+\frac {1}{2} a x^2 y(x)-\frac {a x}{2}+\frac {b^3 x^3}{8}+\frac {3}{4} b^2 x^2 y(x)+\frac {b^2 x^2}{4}+\frac {3}{2} b x y(x)^2+b x y(x)+y(x)^3+y(x)^2+1 \] ✓ Mathematica : cpu = 0.489397 (sec), leaf count = 141
DSolve[Derivative[1][y][x] == 1 - (a*x)/2 + (b^2*x^2)/4 + (a*b*x^3)/4 + (b^3*x^3)/8 + (a^2*x^4)/16 + (3*a*b^2*x^4)/16 + (3*a^2*b*x^5)/32 + (a^3*x^6)/64 + b*x*y[x] + (a*x^2*y[x])/2 + (3*b^2*x^2*y[x])/4 + (3*a*b*x^3*y[x])/4 + (3*a^2*x^4*y[x])/16 + y[x]^2 + (3*b*x*y[x]^2)/2 + (3*a*x^2*y[x]^2)/4 + y[x]^3,y[x],x]
\[\text {Solve}\left [-\frac {1}{3} (27 b+58)^{2/3} \text {RootSum}\left [\text {$\#$1}^3 (27 b+58)^{2/3}-3\ 2^{2/3} \text {$\#$1}+(27 b+58)^{2/3}\& ,\frac {\log \left (\frac {\sqrt [3]{2} \left (\frac {1}{4} \left (3 a x^2+6 b x+4\right )+3 y(x)\right )}{\sqrt [3]{27 b+58}}-\text {$\#$1}\right )}{2^{2/3}-\text {$\#$1}^2 (27 b+58)^{2/3}}\& \right ]=\frac {(27 b+58)^{2/3} x}{9\ 2^{2/3}}+c_1,y(x)\right ]\] ✓ Maple : cpu = 0.076 (sec), leaf count = 42
dsolve(diff(y(x),x) = -1/2*a*x+1+y(x)^2+1/2*a*x^2*y(x)+b*x*y(x)+1/16*a^2*x^4+1/4*a*x^3*b+1/4*b^2*x^2+y(x)^3+3/4*a*x^2*y(x)^2+3/2*y(x)^2*b*x+3/16*y(x)*a^2*x^4+3/4*y(x)*a*x^3*b+3/4*y(x)*b^2*x^2+1/64*a^3*x^6+3/32*a^2*x^5*b+3/16*a*x^4*b^2+1/8*b^3*x^3,y(x))
\[y \left (x \right ) = -\frac {a \,x^{2}}{4}-\frac {b x}{2}+\RootOf \left (-x +2 \left (\int _{}^{\textit {\_Z}}\frac {1}{2 \textit {\_a}^{3}+2 \textit {\_a}^{2}+b +2}d \textit {\_a} \right )+c_{1}\right )\]