SOLUTION: Solve for n nP4=84 nC2 *show work using factorial notation

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Question 1147295: Solve for n
nP4=84 nC2 *show work using factorial notation
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


I don't see how it makes any sense to ask to show work in factorial notation....

nP4+=+n%28n-1%29%28n-2%29%28n-3%29

nC2+=+%28n%28n-1%29%29%2F2

So

n%28n-1%29%28n-2%29%28n-3%29+=+84%28%28n%28n-1%29%29%2F2%29
%28n-2%29%28n-3%29=42

(n-2) and (n-3) are consecutive positive integers; their product is 42. You should be able to solve that equation by inspection....