1. The problem statement, all variables and given/known data We are given the following differential equation: $$ y+yy'-xy'=0 $$ Let's find the solution. 2. Relevant equations 3. The attempt at a solution So in my course usually we have to do some sort of substitution by the lines of x/y=z or y/x=z. This equation has proven difficult. I have taken a look at wolfram alpha and the y(x)=xv(x) substitution is not one I am familiar with.