I have an assignment due on monday and I am having trouble. It deals with first order differential equations. I have a grasp of the methods, but am having trouble with algebraic manipulation to get the problems into the right form, at least that is where I think my problem lies. If anyone could help I would appreciate it. Even if you could just give me a hint (like think about completing the square) that would be nice.

I solved the first two problems already.

The assignment is attached in a pdf.