\[ \left (x^2-1\right ) y'(x)-y(x) (y(x)-x)=0 \] ✓ Mathematica : cpu = 0.0921561 (sec), leaf count = 21
\[\left \{\left \{y(x)\to \frac {1}{x+c_1 \sqrt {x^2-1}}\right \}\right \}\] ✓ Maple : cpu = 0.019 (sec), leaf count = 20
\[y \relax (x ) = \frac {1}{\sqrt {x -1}\, \sqrt {1+x}\, c_{1}+x}\]