Question

What is the sum of the geometric sequence 3, 15, 75, … if there are 7 terms?

Answer 1

use sum=a1(r^(n-1)-1)/(r-1)

Answer 2

how do i plug it in

Answer 3

sorry it shud be r^n instead of R^9n-1)
n= no. of terms
r= common ratio
a1=first term

Answer 4

thkss

Answer 5

answer shud be 58593

Answer 6

S7 = 3 * 5^7 - 1
------
5 - 1

= 58593