\[ f(x) \left (2 a y(x)+b+y(x)^2\right )+y'(x)=0 \] ✓ Mathematica : cpu = 0.057591 (sec), leaf count = 60
\[\left \{\left \{y(x)\to \sqrt {b-a^2} \tan \left (\sqrt {b-a^2} \int _1^x -f(K[1]) \, dK[1]+c_1 \sqrt {b-a^2}\right )-a\right \}\right \}\]
✓ Maple : cpu = 0.044 (sec), leaf count = 45
\[ \left \{ y \left ( x \right ) =\tanh \left ( \int \!f \left ( x \right ) \,{\rm d}x\sqrt {{a}^{2}-b}+{\it \_C1}\,\sqrt {{a}^{2}-b} \right ) \sqrt {{a}^{2}-b}-a \right \} \]