Jawabanmu

2014-04-20T15:05:38+07:00
R=3
a=15
S5= a.r^n-1/2
=15.3^5-1/2
=1215
un = ar^n-1
u8 = a3^8-1 ; 10935 = a3^7 ; a= 5... trus S5 = a(r^n -1):(r-1) jadi S5 = 605.. C
ok makasih
Jawaban paling cerdas!
2014-04-20T15:36:58+07:00
A = 5
r = 3
s15 = 5 (3^5 - 1) : 3 -1 = 1210 : 2 = 605 

coba cek lagi . semoga membantu ;)
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