## anonymous 5 years ago Write out the first three terms and the last term of ∑(-2i+6) (on top of the sigma sign is 40 and on the bottom i=1) . Use the formula for the sum of the first n terms of an arithmetic sequence find the sum.

1. anonymous

$\sum_{i=1}^{40}(-2i+6)$?

2. anonymous

yes thats how the equation looks

3. anonymous

first three term (-2(1)+6)+(-2(2)+6)+(-2(3)+6)

4. anonymous

last three term same thing start from 38, 39,40

5. anonymous

thank you I really appreciate the help

6. anonymous

Do you need help with arithemtic sum? Also if I helped you some way, please fan me

7. anonymous

I understand arithmetic sum now thanks to you help but I do need help with another problem.