(n+2)/n!=56

I'm new to this and having trouble trouble breaking this down, could someone please give me a hint to get this started?

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- December 8th 2008, 09:24 PMCarrickfactorial notation help
(n+2)/n!=56

I'm new to this and having trouble trouble breaking this down, could someone please give me a hint to get this started? - December 8th 2008, 09:29 PMchiph588@
you are saying to divide by and get 56.

This can never happen though...

Are you sure you have the right problem? - December 8th 2008, 09:33 PMCarrick
Sorry,

(n+2)!/n!=56 - December 8th 2008, 09:38 PMchiph588@
Note that

So

Do you see where to go now? - December 8th 2008, 09:42 PMwinsome
Given: (n + 2)!/n! = 56

(n + 2)(n + 2 - 1)(n + 2 - 2)!/n! = 56

(n + 2)(n + 1) = 56

n + 2 = 56 or n + 1 = 56

Which gives n = 54, 55

May be it helps You - December 8th 2008, 09:49 PMchiph588@
You solved that wrong...

So

- December 8th 2008, 09:56 PMCarrick
thanks for the help chip, when down to

(n+9)(n-6) how do you know which to make positive and negative?

eg how do you know its not (n+6)(n-9) without substiting into the initial equation? - December 8th 2008, 10:06 PMchiph588@
its simple factoring

given that

doing foil...

So and

By inspection it can be seen - December 9th 2008, 01:16 AMmr fantastic