Question

What is the 10th term of the geometric sequence –1, 3, –9, …?


19,683

2,187

–59,049

–6,561

Answer 1

19683

Answer 2

The equation is just multiply by three, every other number you add a negative sign.

Answer 3

In the language of geometric series, the series is
s1 = a
s2 = ar
s3 = ar^2
...
sn = ar^(n-1)

What is a and r here?

Once you've found them, the 10th term,

s(10) = ar^9