Question

How do you find the sum of an arithmetic sequence?

Answer 1

3, 9, 15..., if there are 26 terms?

Answer 2

\[\frac{n}{2}(a_1+a_n)\] in your case \[n=26,a_1=3,a_n=a_{26}=3+25\times 6\]

Answer 3

so the answer would be 2028?

Answer 4

i don't know i didn't do it, hold on

Answer 5

that is what i get, yes

Answer 6

okay great, thank you