prove that


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

Left side

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

≠ 3n+2

the statement is false