Here's the problem:

At any point of intersection of a solution curve of the d.e. y'=x+y and the line x+y=0, the function y at that point

(a) is equal to 0

(b) is a local maximum

(c) has a local minimum

(d) has a point of inflection

(e) has a discontinuity

First, what does "d.e." mean? Derivative?

Second, I have no clue how to figure this out, so any help would be much appreciated!