# Math Help - ODE

1. ## ODE

What method should I use to solve the equation $(x+y)dx-(x-y)dy=0$ ? It looks like I might need to find an integrating factor to make it exact, but maybe there's a simpler way?

2. It's homogeneous. That would seem to be another approach.

3. We haven't covered homogeneous equations yet. Is there another way to solve it? There are more problems like this that I am struggling with--they are from page 131 of Elementary Differential Equations (Boyce, DiPrima).

4. Hi. Can't think of one. Standard approach for these is to let $y=vx$, get it in terms of x and v. Separate, integrate, then back substitute v=y/x. Maybe another way though.