Question

What is the 8th term of the geometric sequence –1, 3, –9, …?

Answer 1

I got 19,683

Answer 2

Hmm...see, it's not -3^8, but -3^7. This is because -1 is also included. Got it?

Answer 3

3^7 actually

Answer 4

yeah kind of

Answer 5

Because the nth number when n is even is positive.

Answer 6

Got it?

Answer 7

\(\Large \color{MidnightBlue}{\Rightarrow -1 * -3^{n -1} }\)
Here I give you the formula ;P

Answer 8

common ratio r = 3 / -1 = -3
8th term = a1 * r^7
= -1* (-3)^7

Answer 9

3^7 = 2187.
2187 is correct

Answer 10

oh ok thanks