\[ (x-y(x)) y''(x)+\left (-y'(x)-1\right ) \left (y'(x)^2+1\right )=0 \] ✓ Mathematica : cpu = 27.8965 (sec), leaf count = 18840
DSolve[(-1 - Derivative[1][y][x])*(1 + Derivative[1][y][x]^2) + (x - y[x])*Derivative[2][y][x] == 0,y[x],x]
\[ \text {Too large to display} \] ✓ Maple : cpu = 0.693 (sec), leaf count = 106
dsolve(diff(diff(y(x),x),x)*(x-y(x))-(diff(y(x),x)+1)*(diff(y(x),x)^2+1)=0,y(x))
\[y \left (x \right ) = x +\operatorname {RootOf}\left (-x +\int _{}^{\textit {\_Z}}-\frac {c_{1}^{2} \textit {\_f}^{2}-1}{c_{1}^{2} \textit {\_f}^{2}+\sqrt {-c_{1}^{2} \textit {\_f}^{2}+2}\, c_{1} \textit {\_f} -2}d \textit {\_f} +c_{2}\right )\]