## ridgeboy36 3 years ago what is the 7th term of the geometric sequence -1,4,-16,...? Answers to choose from. a)-16,384 b)-4,096 c)4,096 d)16,384

1. Skaematik

\[T _{n}=ar ^{n-1}\]

2. Skaematik

a= first term r = ratio between consecutive terms n = number of terms

3. ridgeboy36

ok

4. ridgeboy36

@yummydum

5. ridgeboy36

@geoffb

6. ridgeboy36

Can anybody solve this??

7. geoffb

Yeah, use @Skaematik's formula. Just plug in what you know.

8. geoffb

To get \(r\), what are you multiplying between each term?

9. ridgeboy36

@Skaematik are you sure the formula is right i got -4,096 and i dont believe that to be correct

10. geoffb

-1 times what gives you 4? 4 times what gives you -16?

11. ridgeboy36

-4

12. geoffb

Well, the first thing to check is that it's negative. Since it's odd, and your odd terms are negative, it makes sense that it, too, is negative.

13. ridgeboy36

ok

14. geoffb

Why don't you think -4096 is correct?

15. ridgeboy36

because i thought it would have came out positive to 4,096 but i got -4,096

16. geoffb

-4096 is correct.

17. ridgeboy36

ohh thank you both of you @geoffb @Skaematik