Question

Suku ke-4 dan suku ke-9 suatu barisan aritmetika berturut turut 14 dan 29. suku ke-27 barisan tsb adalah ​

Answer 1

=>> u9 = a + 8b = 29

=>> u4 = a + 3b = 14

____________________ _

=>> 5b = 15

=>> b = 3

=>> 14 = a + 3b

14 = a + 3(3)

14 = a + 9

a = 14 - 9

a = 5

Un = a + (n-1)b

U27 = 5 + (27-1)3

U27 = 5 + (26)3

U27 = 5 + 78

U27 = 83

Answer 2

~barisan dan Deret

U₄ = a + 3b = 14

U₉ = a + 8b = 29

-------------------------- [ - ]

              5b = 15

                 b = 3

a = 14 - 3b

a = 5

Un = a + (n - 1) b

U₂₇ = 5 + 26 . 3

U₂₇ = 83