Question

Barisan aritmatika U2=7 U15=19,,,,, tentukan U9 toling berikan caranya

Answer 1

 U2 = 7 => a + 1. b = 7                       a = suku awal
 U15= 19 => a+ 14.b =19 _                  b = beda
                         -13b = -12
                            b = 12/ 13
b= 12/ 13 disubtitusikan ke a+ 6b = 7 => a + 12/ 13 =7
=> a +12/ 13 =7
       a    = 7 - 12/ 13
         a  = 79/ 13
jadi U9 = a + 8. 12/ 13
           = 79/ 13 + 96/ 13
           = 175/ 13
           = 13 6/13

semoga membantu
maaf jika terjadi kesalahan

Answer 2

U2  =>a+b     =7
u15=>a+14b =19
         _________ -
           -13b=-12
                 b=12/13
u2=>a+12/13=7
a=7-12/13=6 1/13

un=6 1/13+(n-1)12/13

u9=6 1/13+(9-1)12/13=
6 1/13 + 7 5/13= 13 6/13