Question

What is the sum of an 8-term geometric series if the first term is 15 and the last term is -4,199,040? (3 points)

-3,599,175

-3,359,230

-3,119,285

-2,879,340

Answer 1

Have you considered building it?

Term1 15
Term2 15*r
Term3 15*(r^2)
...
Term8 15*(r^7)

Answer 2

Im Confused

Answer 3

What is r

Answer 4

It doesn't matter. It's a geometric series. It has a common ratio, r. Just go with it.

Add up the 8 terms and see what happens.

Answer 5

15 + 15*r + 15*(r^2) + ... + 15*(r^7) = 15(1 + r + (r^2) + ... + (r^7))

Are we getting anywhere?