\[ y'(x)=\frac {x \sqrt {4 a x-y(x)^2}+2 a}{y(x)} \] ✓ Mathematica : cpu = 1.15176 (sec), leaf count = 101
DSolve[Derivative[1][y][x] == (2*a + x*Sqrt[4*a*x - y[x]^2])/y[x],y[x],x]
\[\left \{\left \{y(x)\to -\frac {\sqrt {4096 a^5 x-256 a^4 x^4+32 a^2 e^{c_1} x^2-e^{2 c_1}}}{32 a^2}\right \},\left \{y(x)\to \frac {\sqrt {4096 a^5 x-256 a^4 x^4+32 a^2 e^{c_1} x^2-e^{2 c_1}}}{32 a^2}\right \}\right \}\] ✓ Maple : cpu = 0.221 (sec), leaf count = 27
dsolve(diff(y(x),x) = (2*a+x*(-y(x)^2+4*a*x)^(1/2))/y(x),y(x))
\[-\sqrt {-y \left (x \right )^{2}+4 a x}-\frac {x^{2}}{2}-c_{1} = 0\]