Thread: factorial 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?

you are saying to divide by and get 56.

This can never happen though...
Are you sure you have the right problem?

Sorry,

(n+2)!/n!=56

Note that

So

Do you see where to go now?

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

You solved that wrong...



So

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?

its simple factoring

given that

doing foil...

So and

By inspection it can be seen

Originally Posted by chiph588@

You solved that wrong...



So

Small correction: n = -9, 6.

But only n = 6 is a valid solution to the original equation (to the OP: why?).