\[ \left (x y'(x)-y(x)\right ) \left (a x^2+b x+c\right )+x^2-y(x)^2=0 \] ✓ Mathematica : cpu = 0.281941 (sec), leaf count = 132
\[\left \{\left \{y(x)\to -\frac {x \left (-1+\exp \left (\frac {4 \tan ^{-1}\left (\frac {2 a x}{\sqrt {4 a c-b^2}}+\frac {b}{\sqrt {4 a c-b^2}}\right )}{\sqrt {4 a c-b^2}}+2 c_1\right )\right )}{1+\exp \left (\frac {4 \tan ^{-1}\left (\frac {2 a x}{\sqrt {4 a c-b^2}}+\frac {b}{\sqrt {4 a c-b^2}}\right )}{\sqrt {4 a c-b^2}}+2 c_1\right )}\right \}\right \}\] ✓ Maple : cpu = 0.055 (sec), leaf count = 58
\[ \left \{ y \left ( x \right ) =-\tanh \left ( { \left ( {\it \_C1}\,\sqrt {4\,ac-{b}^{2}}+2\,\arctan \left ( {\frac {2\,ax+b}{\sqrt {4\,ac-{b}^{2}}}} \right ) \right ) {\frac {1}{\sqrt {4\,ac-{b}^{2}}}}} \right ) x \right \} \]