\[ a y'(x)^2-y(x) y'(x)-x=0 \] ✓ Mathematica : cpu = 0.865931 (sec), leaf count = 57
\[\text {Solve}\left [\left \{x=\frac {a K[1] \sinh ^{-1}(K[1])}{\sqrt {K[1]^2+1}}+\frac {c_1 K[1]}{\sqrt {K[1]^2+1}},y(x)=a K[1]-\frac {x}{K[1]}\right \},\{y(x),K[1]\}\right ]\] ✓ Maple : cpu = 0.094 (sec), leaf count = 262
\[\left \{\frac {-c_{1} y \left (x \right )+c_{1} \sqrt {4 a x +y \left (x \right )^{2}}+\sqrt {-\frac {2 \left (-2 a^{2}-2 a x -y \left (x \right )^{2}+\sqrt {4 a x +y \left (x \right )^{2}}\, y \left (x \right )\right )}{a^{2}}}\, x +\left (y \left (x \right )-\sqrt {4 a x +y \left (x \right )^{2}}\right ) \arcsinh \left (\frac {-y \left (x \right )+\sqrt {4 a x +y \left (x \right )^{2}}}{2 a}\right )}{\sqrt {\frac {2 y \left (x \right )^{2}+4 \left (a +x \right ) a -2 \sqrt {4 a x +y \left (x \right )^{2}}\, y \left (x \right )}{a^{2}}}} = 0, \frac {c_{1} y \left (x \right )+c_{1} \sqrt {4 a x +y \left (x \right )^{2}}+\sqrt {\frac {2 a^{2}+2 a x +y \left (x \right )^{2}+\sqrt {4 a x +y \left (x \right )^{2}}\, y \left (x \right )}{a^{2}}}\, x -\frac {\sqrt {2}\, \left (y \left (x \right )+\sqrt {4 a x +y \left (x \right )^{2}}\right ) \arcsinh \left (\frac {y \left (x \right )+\sqrt {4 a x +y \left (x \right )^{2}}}{2 a}\right )}{2}}{\sqrt {\frac {y \left (x \right )^{2}+2 \left (a +x \right ) a +\sqrt {4 a x +y \left (x \right )^{2}}\, y \left (x \right )}{a^{2}}}} = 0\right \}\]