Bantuannya ya kak pakai carannnya makasihhh

Mapel : Matematika
Bab : Barisan dan Deret Geometri

Un = ar^n-1
U3 = ar^3-1
18 = ar^2

Un = ar^n-1
U5 = ar^5-1
162 = ar^4

ar^4 / ar^2 = 162/18
            r^2 = 9
               r  = √9
                r = 3

18 = ar^2
18 = a x 3^2
18 = a x 9
 a  = 18/9
 a  = 2

Un = ar^n-1
U9 = 2 x 3^9-1
U9 = 2 x 3^8
U9 = 2 x 6.561
U9 = 13.122

u3 = 18
u5=162

b=
u^5-3 = 162:18
u²= 9
B= √9 = 3

u^9-5 = 4
jadi
u9 = u5 .3⁴
162.81 =13122