\[ x^2 y''(x)-\sqrt {a x^2 y'(x)^2+b y(x)^2}=0 \] ✗ Mathematica : cpu = 1.01481 (sec), leaf count = 0 , could not solve
DSolve[-Sqrt[b*y[x]^2 + a*x^2*Derivative[1][y][x]^2] + x^2*Derivative[2][y][x] == 0, y[x], x]
✓ Maple : cpu = 2.408 (sec), leaf count = 60
\[\left \{-{\mathrm e}^{c_{2}+\int _{}^{\ln \left (x \right )}\RootOf \left (c_{1}-\textit {\_b} +\int _{}^{\textit {\_Z}}-\frac {y \left (x \right )}{\textit {\_a}^{2} y \left (x \right )-\textit {\_a} y \left (x \right )-\sqrt {\left (\textit {\_a}^{2} a +b \right ) y \left (x \right )^{2}}}d \textit {\_a} \right )d \textit {\_b}}+y \left (x \right ) = 0\right \}\]