1. The problem statement, all variables and given/known data Solve using an appropriate substitution ydx+(1+ye^x)dy=0 2. Relevant equations N/A 3. The attempt at a solution u=y du/dx=dy/dx u+(1+ue^x)du/dx=0 This is where it gets really sticky for me. I can't see it being a separable variable problem because it seems impossible to separate the u and the x. It also seems very unlikely that it is a linear d.e. or a bernoulli d.e. because the integrating factor would be e^∫(1/(1+ue^x)dx ) which seems impossible to do. The answer is e^(-x)=ylny+cy.