\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) =1/2\,{\frac {1+2\,\sqrt {4\,{x}^{2}y \left ( x \right ) +1}{x}^{3}+2\,{x}^{5}\sqrt {4\,{x}^{2}y \left ( x \right ) +1}+2\,{x}^{6}\sqrt {4\,{x}^{2}y \left ( x \right ) +1}}{{x}^{3}}}=0} \]
Mathematica: cpu = 0.388549 (sec), leaf count = 74 \[ \left \{\left \{y(x)\to \frac {-160 c_1 x^7-200 c_1 x^6-400 c_1 x^4+400 c_1^2 x^2+16 x^{12}+40 x^{11}+25 x^{10}+80 x^9+100 x^8+100 x^6-100}{400 x^2}\right \}\right \} \]
Maple: cpu = 0.297 (sec), leaf count = 40 \[ \left \{ -{\it \_C1}+{\frac {1}{x} \left ( -4\,{x}^{6}-5\,{x}^{5}-10\,{ x}^{3}+10\,\sqrt {4\,{x}^{2}y \left ( x \right ) +1} \right ) }=0 \right \} \]