Get the differential equation. Test whether the equation M(x,y)dx + N(x,y)dy homogenous or not. If f(x,y)=0, we can test it by f(kx,ky)=k^n(x,y). If M(x,y) and N(x,y) are both homogenous (degree n are the same) If not homogenous (degree n are different) The ratio M/N or N/M can be expressed of a single variable, say v. State non homogenous and don't need to solve for the general solution. Then the substitution of x=vy or y=vx transforming to a variable separable D.E. We can use if M is simpler, x=vy We can use if M is simpler, y=vx Proceed to substitution Transform the equation to a variable separable equation by means of separation of variable. If then the general solution will be