math B30

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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

  • math B30 -

    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

  • math B30 -

    i don't understand how you get r?

  • math B30 -

    nvm i got i thank you so much

  • math B30 -

    Mathe matics

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