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Math Help - Need Help with simple geometric sequence

  1. #1
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    Need Help with simple geometric sequence

    In the sequence 2,6,18,..., which term is number 162?

    162 = 2 x 3^(n -1)
    is this how you start it?
    then i get 81 = 3^(n-1)

    how do i solve that without using a calculator?
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  2. #2
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    simply try to find out:

    3^1 = 3 < 81
    3^2 = 9 < 81
    3^3 = 27 < 81
    etc.
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  3. #3
    Senior Member euclid2's Avatar
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    Quote Originally Posted by NeedHelp18 View Post
    In the sequence 2,6,18,..., which term is number 162?

    162 = 2 x 3^(n -1)
    is this how you start it?
    then i get 81 = 3^(n-1)

    how do i solve that without using a calculator?
     t_5
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