Find the sum of the given arithmetic series. 24 + 17 + 10 + 3 + … + (-39)

Question

Find the sum of the given arithmetic series.
24 + 17 + 10 + 3 + … + (-39)

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Thiên Ân 1 month 2021-08-12T08:30:06+00:00 1 Answers 0 views 0

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    2021-08-12T08:31:11+00:00

    Answer:

    -75

    Step-by-step explanation:

    -39 = 24 +(n-1)(-7)

    -39 = 24 +7-7n

    -39 = 31-7n

    7n = 31+39

    7n=70

    n=10

    the sum = 10/2 × (24-39)

    = 5 × -15

    = 75

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