## Precalculus (6th Edition) Blitzer

$2+4+6=3(3+1)$, $2+4+6+...+ 2(k+1)=(k+1)(k+2)$.
Following the previous statements, we have: If $n=3$, the statement is $2+4+6=3(3+1)$ If $n=k+1$, the statement is $2+4+6+...+ 2(k+1)=(k+1)(k+2)$.