Question

Find the sum of the first 12 terms of the sequence. Show all work for full credit.

1, -4, -9, -14, . . .

Answer 1

-318 . It's an Arithmetic Progression with common difference= -5

Answer 2

It is arithmetic sequence why don't use the proper formula.

Answer 3

The formula is n/2* (2*a+ (n-1)*d)
where n= no. of terms (12 here), a = 1st term (1 here) and d= common difference ( -5 here)

Answer 4

thank you! :)