How Can y(x) Be Expressed as a Convolution in This Differential Equation?

[tandoorichicken]

Any hints to this problem?

"Assume the solution to a differential equation is given by
\frac{dy(x)}{dx}+ay(x) = f(x)
where y(0)=y_0 and a is a constant. Show how y(x) can be written as a convolution of f(x) and an exponential e^{ax}."

The only hint we got from the prof was to multiply both sides by the exponential and express the left as a single term, but I could be doing something wrong there as well. Anyone have any more hints? (I don't want the solution just yet, I just want to try to work it out first)

Thanks

 

[doodle]

Upon multiplying both sides with the exponential, recall next that
\frac{d(uv)}{dx} = u\frac{dv}{dx} + v\frac{du}{dx}