suatu barisan aritmatika mempunyai U4=14 dan U8=26 ,tentukan suku ke-zonya

U8 = a + 7b = 26
U4 = a + 3b = 14
= 4b = 12
=. b = 12/4
b = 3
U8 = a + 7b = 26
U8 = a + 7(3) = 26
U8 = a + 21 = 26
U8 = a = 26-21
U8 = a = 5

U20 = a + 19b
U20 = 5 + 19(3)
U20 = 5 + 57
U20 = 62