\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) =-x/2+1+{x}^{2}\sqrt {{x}^{2}-4\,x+4\,y \left ( x \right ) }=0} \]
Mathematica: cpu = 0.191024 (sec), leaf count = 36 \[ \left \{\left \{y(x)\to \frac {1}{36} \left (-24 c_1 x^3+36 c_1^2+4 x^6-9 x^2+36 x\right )\right \}\right \} \]
Maple: cpu = 0.171 (sec), leaf count = 25 \[ \left \{ {\it \_C1}+{\frac {2\,{x}^{3}}{3}}-\sqrt {{x}^{2}-4\,x+4\,y \left ( x \right ) }=0 \right \} \]