We're assuming that it has already been shown that the field is conservative.

I don't think I'm quite understanding how to do this.

So far, I have:

So, then I take the first one and integrate it with respect to x and get:

Then I find:

and set this equal to from above:

So I take the integral of this and get:

I'm not sure of what to do now.

The final answer to the problem is