barisan geometri u8=512 dan u5=64 ditanya rasio

u8 = 512
a[tex] r^{7} [/tex] = 512

u5 = 64
a[tex] r^{4} [/tex] = 64

[tex] \frac{u8}{u5} = \frac{512}{64} \\ \frac{ar^{7}}{ar^{4}} = 8 \\ r^{3} = 8 \\ r = 2[/tex]