What is the 9th term of the geometric sequence 4, -20, 100, ...

-312,500
-12,500
62,500
1,562,500
10 points for best answer!

a = 4, r = -5
t(n) = ar^(n-1)
so t(9) = 4(-5)^8 = 1,562,500 <------

1562500

The formula is a*r^n-1(Read as a times r to the power of n-1)
here, a =4
r = -5
n=9

There ! I did your homework for you!