1. The problem statement, all variables and given/known data Find an integrating factor for: xdy - (y + x^2 + 9y^2)dx = 0 2. Relevant equations P(x,y)dx + Q(x,y)dy = 0 Δμ = μyP - μxQ. where μ is the integrating factor. 3. The attempt at a solution well, I don't know what I should do. I can use the formula I wrote but that would lead to solving a PDE. any ideas?