Question

Jumlah suku ke 3 adlah 11 dan suku ke 7 27 maka jumlah 10 suku pertama adalah?

Answer 1

Verified answer

Materi: Barisan dan Deret

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Answer 2

Verified answer

Bab Barisan dan Deret
Matematika SMP Kelas IX

Aritmatika
b = (Un - Up) / (n - p)
b = (27 - 11) / (7 - 3)
b = 16 / 4
b = 4

a = U3 - 2 x b
a = 11 - 2 x 4
a = 11 - 8
a = 3

Sn = (n/2) x (2a + (n - 1) b)
S10 = (10/2) x (2 x 3 + 9 x 4)
S10 = 5 x (6 + 36)
S10 = 5 x 42
S10 = 210