If the seventh term of a geometric series is 192, and the first term is 3, find the sum of the first 8 terms of the series

Answer 1

ar^6 = 192 , a=3
r^6 = 192/3 = 64
r = 2

sum(8) =a(r^8 - 1)/(r-1)
= 3(256-1)/(2-1) = 765

Answer 2

i don't understand how you get r?

Answer 3

nvm i got i thank you so much

Answer 4

Mathe matics