I must solve a lot of DE's. I'm finishing my vacations and the upper level undergraduate courses of physics are coming very soon. I just begin with DE's. I hope to improve quickly.

Find the general solution of this DE:

$\displaystyle y'+3y=x+e^{-2x}$.

I don't expect a full solution. First, I'd be glad to know what kind of DE it is and the way to solve it. Maybe a reference about this thread: http://www.mathhelpforum.com/math-he...-tutorial.html can be nice.

Thanks for the help.