Jawabanmu

2014-03-26T20:01:19+07:00
A) U5 = ar^4 = 162
U3 = ar^2 = 18
______________ :
r^2 = 9
r = 3
jadi rasionya = 3

b) ar^2 = 18
a.3^2 = 18
a.9 = 18
a = 18/9
a = 2
suku pertama = 2
U8 = ar^7
= 2.3^7
= 2.2187
= 5374

c)S8 = 2(3^8 - 1) / (3 - 1)
= 2(6561 - 1) / 2
= 2.6560 / 2
= 6560
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