\[ a+\left (x^2-1\right ) y'(x)-x y(x)=0 \] ✓ Mathematica : cpu = 0.0240529 (sec), leaf count = 21
\[\left \{\left \{y(x)\to a x+c_1 \sqrt {x^2-1}\right \}\right \}\] ✓ Maple : cpu = 0.017 (sec), leaf count = 20
\[\left \{y \left (x \right ) = a x +c_{1} \sqrt {x +1}\, \sqrt {x -1}\right \}\]