Dik: 5,8,11,...,125,128,131 Dit: suku ke 22?

Un = an + b

8 = 2a + b
5 = a + b —
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3 = a

* 5 = 3 + b
b = 5 - 3
b = 2

Rumus = Un = 3n + 2

U22 = 3.22 + 2
U22 = 66 + 2
U22 = 68


Maaf jika ada kesalahan ^^