\[ a+2 y(x) y''(x)-y'(x)^2=0 \] ✓ Mathematica : cpu = 0.0053534 (sec), leaf count = 31
\[\left \{\left \{y(x)\to \frac {x^2 \left (-a+c_1{}^2\right )}{4 c_2}+c_1 x+c_2\right \}\right \}\] ✓ Maple : cpu = 1.189 (sec), leaf count = 24
\[\left \{y \left (x \right ) = c_{1} x +c_{2}+\frac {\left (c_{1}^{2}-a \right ) x^{2}}{4 c_{2}}\right \}\]