Step-by-step explanation:
Did you mean
[tex] = \sum \limits_{n = 2}^{4} (n + 1)[/tex]
[tex] = (2 + 1) + (3 + 1) + (4 + 1)[/tex]
[tex] = 3 + 4 + 5[/tex]
[tex] = 12[/tex]