CPM Homework Help : INT3 Problem 12-43

Calculate each sum.

Hint:

Write out the first few and last term of the series.

$\displaystyle\sum _ { n = 1 } ^ { 8 } 3 ^ { n }$
Hint (a):
This series is geometric.

$\displaystyle\sum _ { c = 1 } ^ { 16 } ( 3 c + 5 )$
Hint (b):
This series is arithmetic.
Answer (b):
$488$