\[ \left (x^2-1\right ) y'(x)-y(x) (y(x)-x)=0 \] ✓ Mathematica : cpu = 0.0751822 (sec), leaf count = 21
\[\left \{\left \{y(x)\to \frac {1}{x+c_1 \sqrt {x^2-1}}\right \}\right \}\] ✓ Maple : cpu = 0.017 (sec), leaf count = 20
\[ \left \{ y \left ( x \right ) = \left ( \sqrt {x-1}\sqrt {1+x}{\it \_C1}+x \right ) ^{-1} \right \} \]