This question: If $x^2\pm px \mp q$ both factor into terms with integer coefficients, then $p$ and $q$ are the hypotenuse and area of a right triangle. is an exact copy of an AoPS question. I flagged it yesterday. Why did not the moderators take care of this?
A couple of comments:
If you suspect that a problem has been plagiarized, please flag it for moderator attention. Please include a link to the original source in the flag, as this will make it easier to track down. In general, it is not appropriate to post copyrighted material onto Math SE. Please also note that flags can sometimes take time to be dealt with, particularly on the weekend. If it has not been handled after a day or two, please feel free to poke one of the moderators in the Math Mods' Office. Both quid and I are generally @-pingable there.
If you believe that a problem has been plagiarized, and is therefore inappropriate for Math SE, do not answer it. If you find out after the fact that the question is plagiarized, it would be appropriate to delete any answer which you have provided. If, after a moderator handles your flag, you decide that the question is appropriate, you can always undelete your answer.
That being said, the situation here is a bit muddled. For one thing, AoPS does not own the copyright on that post (it is owned by the original poster). Moreover, with an appropriate citation, I think a good case can be made that fair use applies. Finally, while a particular presentation of a problem can be copyrighted, mathematics itself cannot be copyrighted. In the case of a short problem like this, I am not sure where the line between mathematical content and presentation is, precisely.
I have added a link to the original AoPS question and cleaned up the formatting a bit. I am not going to take any other action at this time.