\[ x^2 \left (a y(x)^2+y'(x)\right )-b=0 \] ✓ Mathematica : cpu = 0.0985813 (sec), leaf count = 51
DSolve[-b + x^2*(a*y[x]^2 + Derivative[1][y][x]) == 0,y[x],x]
\[\left \{\left \{y(x)\to -\frac {-1+\sqrt {4 a b+1} \left (-1+\frac {2 c_1}{x^{\sqrt {4 a b+1}}+c_1}\right )}{2 a x}\right \}\right \}\] ✓ Maple : cpu = 0.053 (sec), leaf count = 41
dsolve(x^2*(diff(y(x),x)+a*y(x)^2)-b = 0,y(x))
\[y \left (x \right ) = \frac {-\tanh \left (\frac {\sqrt {4 a b +1}\, \left (-\ln \left (x \right )+c_{1}\right )}{2}\right ) \sqrt {4 a b +1}+1}{2 a x}\]