Assuming that p not equals to $0$, state conditions under which the linear differential equation
is separable. If the equation satisfies these conditions, solve it by separation of variables and by one other method.
What i tried
Im confused about this question, because I think this is a linear equation and could be solve by the integrating factor method and i dont see how the seperable method can be used. What it attempted was to move the RHS of the equation to the LHS to give $y'+p(x)y-f(x)=0$. I then divide the LHS of the equation by $f(x)$ , my guess is that this equation is seperable only when $f(x)=p(x)$. However im stuck from here onwards. Could anyone help me with this. Thanks