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Ashy98

  • one year ago

What is the sum of the arithmetic sequence 3, 9, 15..., if there are 26 terms? A.) 2,028 B.) 1,452 C.) 2,268 D.) 1,728

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  1. mathstudent55
    • one year ago
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    1. find the 26th term 2. add the first 26 terms

  2. mathstudent55
    • one year ago
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    What is the common difference?

  3. mathstudent55
    • one year ago
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    To find the common difference, subtract a term from the next term.

  4. mathstudent55
    • one year ago
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    d = common difference = 9 - 3 = 15 - 9 What is d?

  5. Ashy98
    • one year ago
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    the answer would be A

  6. mathstudent55
    • one year ago
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    Formula to find the nth term: \(\large a_n = a_1 + d(n - 1)\) Formula to find the sum of the first n terms: \(\large S_n = \dfrac{n(a_1 + a_n)}{2} \) Using the formulas above, you get: \(a_n = 153\) \(S_n = 2028\)

  7. mathstudent55
    • one year ago
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    You are correct.

  8. Ashy98
    • one year ago
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    okay thank you!(:

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