Well, if it's exact then you have

\(\displaystyle 1 + \left ( e^y - x \right ) \dfrac{dy}{dx} = 0\)

and you have the general form

\(\displaystyle M(x, y) + N(x, y) \dfrac{dy}{dx} = 0\)

then what are M(x, y) and N(x, y) and how do you use them?

Let us know what you've got and we'll go from there. The solution method isn't particularly hard but it does require some intuition.

-Dan