\[ (a-1) b+a x^2+2 a x y(x) y'(x)+(1-a) y(x)^2+y(x)^2 y'(x)^2=0 \] ✓ Mathematica : cpu = 0.873793 (sec), leaf count = 79
\[\left \{\left \{y(x)\to -\sqrt {-2 a c_1 x+a c_1{}^2+b-x^2+2 c_1 x-c_1{}^2}\right \},\left \{y(x)\to \sqrt {-2 a c_1 x+a c_1{}^2+b-x^2+2 c_1 x-c_1{}^2}\right \}\right \}\] ✓ Maple : cpu = 0.664 (sec), leaf count = 195
\[\left \{y \left (x \right ) = \sqrt {-a \,x^{2}+b}, y \left (x \right ) = \frac {\sqrt {\left (c_{1}+\left (-x^{2}+b \right ) a -b -2 \sqrt {-\left (-c_{1}+b \right ) \left (a -1\right ) a}\, x \right ) a}}{a}, y \left (x \right ) = \frac {\sqrt {\left (c_{1}+\left (-x^{2}+b \right ) a -b +2 \sqrt {-\left (-c_{1}+b \right ) \left (a -1\right ) a}\, x \right ) a}}{a}, y \left (x \right ) = -\sqrt {-a \,x^{2}+b}, y \left (x \right ) = -\frac {\sqrt {\left (c_{1}+\left (-x^{2}+b \right ) a -b -2 \sqrt {-\left (-c_{1}+b \right ) \left (a -1\right ) a}\, x \right ) a}}{a}, y \left (x \right ) = -\frac {\sqrt {\left (c_{1}+\left (-x^{2}+b \right ) a -b +2 \sqrt {-\left (-c_{1}+b \right ) \left (a -1\right ) a}\, x \right ) a}}{a}\right \}\]