Barisa aritmetika U3=16 U6=7 tentukan suku ke-8

U3 = 16
U6 = 7

a + 2b = 16
a + 5b = 7
________ –
– 3b = 9
b = – 3

a + 5(-3) = 7
a – 15 = 7
a = 22

U8 = a + 7b
U8 = 22 + 7 (- 3)
U8 = 22 + ( – 21)
U8 = 1