\[ a x^n f\left (y'(x)\right )+x y'(x)-y(x)=0 \] ✓ Mathematica : cpu = 0.112931 (sec), leaf count = 67
\[\text {Solve}\left [\left \{a f(\text {K$\$$5321505}) x^n+\text {K$\$$5321505} x=y(x),\left (f(\text {K$\$$5321505})^{\frac {1}{n}-1} \left ((n-1) \int _1^{\text {K$\$$5321505}} -\frac {f(K[1])^{-1/n}}{a n} \, dK[1]+c_1\right )\right ){}^{\frac {1}{n-1}}=x\right \},\{y(x),\text {K$\$$5321505}\}\right ]\]
✓ Maple : cpu = 0.286 (sec), leaf count = 169
\[ \left \{ [y \left ( {\it \_T} \right ) =a \left ( \left ( {\frac {1}{anf \left ( {\it \_T} \right ) } \left ( \left ( 1-n \right ) \int \! \left ( f \left ( {\it \_T} \right ) \right ) ^{-{n}^{-1}}\,{\rm d}{\it \_T}+{\it \_C1}\,an \right ) } \right ) ^{ \left ( n-1 \right ) ^{-1}} \left ( f \left ( {\it \_T} \right ) \right ) ^{{\frac {1}{n \left ( n-1 \right ) }}} \right ) ^{n}f \left ( {\it \_T} \right ) +{\it \_T}\, \left ( {\frac {1}{anf \left ( {\it \_T} \right ) } \left ( \left ( 1-n \right ) \int \! \left ( f \left ( {\it \_T} \right ) \right ) ^{-{n}^{-1}}\,{\rm d}{\it \_T}+{\it \_C1}\,an \right ) } \right ) ^{ \left ( n-1 \right ) ^{-1}} \left ( f \left ( {\it \_T} \right ) \right ) ^{{\frac {1}{n \left ( n-1 \right ) }}},x \left ( {\it \_T} \right ) = \left ( {\frac {1}{anf \left ( {\it \_T} \right ) } \left ( \left ( 1-n \right ) \int \! \left ( f \left ( {\it \_T} \right ) \right ) ^{-{n}^{-1}}\,{\rm d}{\it \_T}+{\it \_C1}\,an \right ) } \right ) ^{ \left ( n-1 \right ) ^{-1}} \left ( f \left ( {\it \_T} \right ) \right ) ^{{\frac {1}{n \left ( n-1 \right ) }}}] \right \} \]