Question

What is the sum of the first 100 terms of the arithmetic sequence 2, 7, 12, 17?

Answer 1

25452

Explanation:

each term goes up by 5 so the formula is 2+5(n-1) where n is the term number

so the equation is ∑n=1 101 (2+5(n-1))

∑n=1 101 (5n-3) = 25452