Question

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

Answer 1

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

Answer 2

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

Answer 3

ok

Answer 4

@yummydum

Answer 5

@geoffb

Answer 6

Can anybody solve this??

Answer 7

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

Answer 8

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

Answer 9

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

Answer 10

-1 times what gives you 4?

4 times what gives you -16?

Answer 11

-4

Answer 12

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.

Answer 13

ok

Answer 14

Why don't you think -4096 is correct?

Answer 15

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

Answer 16

-4096 is correct.

Answer 17

ohh thank you both of you @geoffb @Skaematik