An identical previous post been answered.
The disappearance of the + sign is because you have probably have copied and pasted, and the original + sign was not in ASCII code if it was in another application.
If you have to cut and paste, try to first paste it in an ascii editor, such as notepad, check that everything is ok or make necessary corrections, then paste it to your post.
(Word gives me this: A+B )
The line x plus 7y=5 cuts the circle x^2 plus y^2=15 at the points P & Q. Find: a) P & Q. b) the midpoint of PQ.
(I don't know why, but the plus sign does not show after I submit d question so dats y I wrote it in words)
3 answers
I was d one dat posted d previous question, I had to re-post again cos d plus sign won't show after I click submit
Another possible reason is that your keyboard code has a different value for the "+" sign, which is rare.