Question

Find the sum of the first 8 terms of the sequence. Show all work for full credit.

1, -3, -7, -11, ...

Answer 1

please help!!!!!
common difference is -4 right?
and the first term is 1

Answer 2

This is an arithmetic sequence. Yes indeed, -4 is the common difference, and the first term is 1.

Use the same "sum of an arith. sequence" that I shared with you earlier.

Answer 3

s = a + (n - 1)*d
1 + (8-1)*-4
1+(7)*-4
1+(-28)
-29

Answer 4

is that right?

Answer 5

wait

Answer 6

silly me

Answer 7

-27

Answer 8

You're absolutely on the right track, but I'd strongly suggest y ou enclose that -4 inside parentheses. Label your result: s = 1+(7)*-4

Answer 9

Nice work.