Question

HEEEEELP ! what is the sum of the arithmetic series? Picture below

Answer 1

hold on, I need to wash my hands...

Answer 2

lol can u help?

Answer 3

Sum = (1/2) (number of terms) (first term + last term)

Answer 4

I keep getting 819 but I don't think that's right

Answer 5

if you keep getting 819, it should be right, I hope

Answer 6

is it?! =/

Answer 7

idk. Trust your calculator XD

Answer 8

@nikato can u tell me if my answer is right? I keep getting 819
@sourwing haha okay.. thanks for helping! :) :D

Answer 9

http://www.wolframalpha.com/input/?i=sum+i%3D+1+to+18+%285i-4%29

Answer 10

UR THE BEST THANKS!! I was wrong tho -_-

Answer 11

how can I write this one in? I want to check my answer, I got 2.

Answer 12

@sourwing

Answer 13

shh.. I'm watching pokemon

Answer 14

lol pokemon! XD ill write it in just tell me how

Answer 15

@sourwing

Answer 16

@nikato

Answer 17

This is actually a geometric sequence, so this will help
http://www.mathsisfun.com/algebra/sequences-sums-geometric.html

Answer 18

And if you did it right, you should get around 4 or 3.999877...