suku ke-2 suatu barisan geometri adalah 27 dan suku ke-5nya 8 tentukan suku ke7

U₂ = ar
27 = ar
a = 27/r

U₅ = ar⁴
8 = ar⁴
a = 8/r⁴

a = a
27/r = 8/r⁴
r⁴/r = 8/27
r³ = 8/27
r = ³√(8/27)
r = 2/3

a = 27/r
a = 27/(2/3)
a = 81/2

U₇ = ar⁶
U₇ = (81/2)(2/3)⁶
U₇ = 32/9

semoga membantu ^^