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Find the sum of the first 20 terms of the arithmetic sequence whose gen form is an=23+7n​

Answers

  • Réponse publiée par: cbohol56

    Hello !!

    Find the first term.

    An = 23 + 7n

    A1 = 23 + 7(1)

    A1 = 23 + 7

    A1 = 30

    Find the 20th term.

    An = 23 + 7n

    A20 = 23 + 7(20)

    A20 = 23 + 140

    A20 = 193

    Find the sum of the first 18 terms of the sequence.

    Sn = (n/2) × (A1 + An)

    S20 = (20/2) × (30 + 193)

    S20 = 10 × 223

    S20 = 2230

    Final result : the sum of the first 20 terms is 2230.

    I hope I have collaborated !

  • Réponse publiée par: meteor13

    1 965 is the 20th place in arithmetic

    Step-by-step explanation:

    an = a1 + (n-1) d

    a20 = 122 + (20-1) 97

    a20 = 122 + (19) 97

    a20 = 122 + 1 843

    a20 = 1 965

    *Basta ganito yung formula ikaw na bahala mag mag-compute ng total. :)

  • Réponse publiée par: cbohol56

    1290

    Step-by-step explanation:

    Given:

    n = 20

    A1 = 3

    An = 83

    Formula:

    s_{n} =  \frac{n}{2} ( a_{1} +  a_{n})

    Substitute and calculate.

    s_{n} =  \frac{20}{2} (3 + 83) \\  s_{n} = 10(86) \\ s _{n} = 1290

    The answer is 860.

  • Réponse publiée par: nelspas422

    19nt

    Step-by-step explanation:

  • Réponse publiée par: nelspas422

    answer:

    C.200

    anong subject yan

  • Réponse publiée par: reyquicoy4321

    B. 1100

    Step-by-step explanation:

    the answer is 1100 kbyeee.

  • Réponse publiée par: calmaaprilgrace

    B.780

    Step-by-step explanation:

    n=20,a1= -24,an=102

    Sn=n/2(a1+a2)

    S20=20/2(-24+102)

    S20=10(78)

    S20=780

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  • Réponse publiée par: elaineeee

    It's just a substitution:


    SOLUTION:


    a1 = 23 + 7(1)


    a1 = 30



    Arithmetic Sequence: 30, 37, 44, 51, 58, 65, 72, 79, 86, 93, 100, 107, 114, 121, 128, 135, 142, 149, 156, 163.



    FORMULA: Sn = n(a1 + an) / 2


    S20 = 20 (30 + 163) / 2


    = 10 (193)


    = 1, 930



    ANSWER: The sum of the first 20 terms is 1, 930.

  • Réponse publiée par: dorothy13

    The answer is letter B. - 730

    FIRST TERM a1= - 122;

    NUMBER OF TERMS n=20;

    COMMON DIFFERENCE d=9

    Sn= n/2 [2a1 + (n-1) d]

    S20= 20/2 [2(-122) + (20-1) 9]

    S20= 10 [-244 + 171]

    S20= 10 (-73)

    S20= - 730

  • Réponse publiée par: hannahleigh

    The sum of the first 20 terms of the arithmetic sequence is 780.

    Step-by-step explanation:

    Given:   a_1=-24,   a_n=102,   n=20

    Formula:   S_n=\frac{n}{2}(a_n+a_1)

    Substitute the given in the formula to find the sum of the first 20 terms

    S_{20}=\frac{20}{2}(-24+102)\\S_{20}=10(78)\\S_{20}=780

    #CarryOnLearning

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Find the sum of the first 20 terms of the arithmetic sequence whose gen form is an=23+7n​...