Question

Can someone help me?
What is the sum of the finite arithmetic series?
(-10)+0+10+20+. . .+130
(-10)*13*14/2-10*13
I got -1,040, but it's not an answer choice.

Answer 1

@hartnn

Answer 2

how did you calculate the sum ?

Answer 3

(-10)*13*14/2-10*13

Answer 4

common difference = d=10
number of terms =n= 15
a1 =-10

\(\Large S_n = (n/2)(2a_1+(n-1)d)\)

Answer 5

\(\Large = (15/2) (2(-10)+14\times 10) \)


calculate that^^

Answer 6

900. : o

Answer 7

ohh!
you took number of terms =14??

Answer 8

yep, did you get how we calculated

a1, n and d

Answer 9

Yah. . .x3