I put this comment under the question above:
Probably the reason for the down-vote and the votes to close the question is that it's phrased in language suitable for assigning homework. That can make people suspect that a question was copied by someone who may not even have understood the question. Instead of simply down-voting and voting to close, they ought to explain that here, but usually they don't.
Could we make it a policy and convention that some notice similar to that (not including the last sentence) should always be included when a question is phrased like a homework assignment? ("Factor this polynomial." "Evaluate this integral." "Show that this holds for every value of $n$." Etc.)
(I've tagged this a feature request, but it's not a request for software changes.)
PS: The notice should be suitable for use before the down-votes or the votes to close actually happen. So I suggest something like this:
Questions posed here should not be phrased in language suitable for assigning homework, merely instructing the reader to solve the problem. They should be phrased in a way that shows that the poster understands the question. If a question is phrased as if they had been merely copied from a homework assignment, that may be considered a reason to down-vote it or to close it.