I'm stuck with these three ODEs:

$\displaystyle u'' - \frac{1}{x}u' - 4x^2u=0$

$\displaystyle x^2 y''(x) + xy'(x)-n^2y(x)=0$

$\displaystyle u''' + 2e^xu'' -u' -2e^xu=0$

Nothing I tried worked, could you please help me? A hint on which method to try would be really great.

Thank you!