SOLUTION: (n+2)!/n!=56 where n=N my answer: n= 7

Algebra ->  Permutations -> SOLUTION: (n+2)!/n!=56 where n=N my answer: n= 7       Log On


   

Question 241099: (n+2)!/n!=56
where n=N
my answer: n= 7

Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
%28n%2B2%29%21%2Fn%21+=+56
%28n%2B2%29%21+=+56+%2A+n%21
%28n%2B2%29%28n%2B1%29n%21+=+56+%2An%21}
%28n%2B2%29%28n%2B1%29+=+56
n%5E2+%2B+3n+-54+=+0
%28n%2B9%29%28n-6%29+=+0
So n = -9 or n=6
Since n=-9 is not possible in n!, then it must be n=6
Which makes sense since n+1=7 and n+2=8 and 7*8 = 56