\[ a \sqrt {x^2+y(x)^2}+x y'(x)-y(x)=0 \] ✓ Mathematica : cpu = 0.0235148 (sec), leaf count = 16
\[\left \{\left \{y(x)\to x \sinh \left (c_1-a \log (x)\right )\right \}\right \}\]
✓ Maple : cpu = 0.028 (sec), leaf count = 33
\[ \left \{ {\frac {{x}^{a}}{x}\sqrt { \left ( y \left ( x \right ) \right ) ^{2}+{x}^{2}}}+{\frac {{x}^{a}y \left ( x \right ) }{x}}-{\it \_C1}=0 \right \} \]