math B30
posted by alix .
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

ar^6 = 192 , a=3
r^6 = 192/3 = 64
r = 2
sum(8) =a(r^8  1)/(r1)
= 3(2561)/(21) = 765 
i don't understand how you get r?

nvm i got i thank you so much

Mathe matics