dari suatu barisan aritmatika diketahui U2=27 dan U6= 19.Berapa U8? Jawab pakai cara Makasih

U2 = a + b = 27
U6 = a + 5b = 19
------------------------(-)
- 4b = 8
b = - 2

a + b = 27
a - 2 = 27
a = 27 + 2
a = 29

U8 = a + 7b
= 29 + 7(-2)
= 29 - 14
= 15

Barisan Aritmetika.

a + b = 27
a + 5b = 19
__________ -
-4b = 8 → b = -2
a - 2 = 27 → a = 29

Un = a + (n - 1)b
U₈ = 29 + (8 - 1)(-2)
     = 15