for the arthritic sequence 5,9,13,17,21,… how many terms would you need to get to 129

Question

for the arthritic sequence 5,9,13,17,21,… how many terms would you need to get to 129

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Helga 7 months 2021-07-25T05:06:07+00:00 1 Answers 3 views 0

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    2021-07-25T05:07:10+00:00

    9514 1404 393

    Answer:

      32

    Step-by-step explanation:

    The first term is 5 and the common difference is 9-5=4, so the n-th term is …

      an = a1 +d(n -1)

      an = 5 +4(n -1) = 4n +1

    Then the term number for the term 129 is …

      129 = 4n +1 . . . . . put the given value in the formula

      128 = 4n  . . . . . . . subtract 1

      32 = n . . . . . . . . . .divide by 4

    The 32nd term is 129.

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