Question

Find the sum of the infinite geometric series: 9 – 6 + 4 – …

Answer 1

use formula :
S = a/(1-r)
for a = the first term
r = ratio

Answer 2

The thing is I don't know how to find r

Answer 3

r = a2/a1 = -6/9 = -2/3

Answer 4

so, S = 9/(1-(-2/3)) = 9/(1+2/3) = 9/(5/3) = ... ?

Answer 5

or u can write into multiplication :
9 * (3/5) = ...