If fg + gh = fh, which of the following statements must be true?

The only safe conclusion is that point G lies on line FH or that point G lies somewhere between line FH. We cannot conclude that point G is the midpoint of line FH eventhough by virtue of definition of midpoint, the given equation is a proof equation. If G were to be midpoint, segment FG must be equal to segment GH in line FH. 

)because it's going in order of the math sign