Find the sum of the first 14 terms of 2, 5, 8, 11, ...
Just add them up!
2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41 !!!!!
Since the first 14 terms are:
2,5,8,11,14,17,20,23,26,29,32,35,38,41
We take the sum of the first one and the last one:
43, and we multiply that by 7,
And we get 43*7.
Can you figure it out from there?
+1712 
