Posted by **4611star** on Sunday, February 19, 2012 at 10:15am.

prove that

2 2 2 2

(n-1) + n + (n+1) = 3n +2

- maths -
**Reiny**, Sunday, February 19, 2012 at 10:31am
Your statement

(n-1) + n + (n+1) = 3n +2

is false

(n-1) + n + (n+1)

= n-1+n+n+1

= 3n

I don't know what 2 2 2 2 is supposed to mean.

- maths -
**Steve**, Sunday, February 19, 2012 at 11:44am
Looks like an attempt at exponents, not counting on html formatting:

(n-1)^2 + n^2 + (n+1)^2 = 3n^2 + 2

Now come on, guy. Just expand the expressions, and the +2n and -2n cancel out, and the +1 and +1 add up to 2.

Where do you have trouble here?

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