Bantu jawab ya,no.4 aja Tolong diberitahukan dengan caranya ya,terimakasih

[tex] \frac{u5}{u2} = \frac{5}{40} \\ \frac{a {r}^{4} }{a {r} } = \frac{1}{8} \\ {r}^{3} = \frac{1}{8} \\ r = \frac{1}{2} [/tex]
[tex]u2 = ar \\ 40 = a \frac{1}{2} \\ a = 80[/tex]
[tex]u8 = a {r}^{7} \\ = 80 \times ( { \frac{1}{2}) }^{7} \\ = 80 \times \frac{1}{128} \\ = \frac{80}{128} = \frac{5}{8} [/tex]
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