5. (logg81) (log264)

5. (log₃81) ⋅ (log₂64)

log₃81 = log₃3⁴ = 4log₃3 = 4

log₂64 = log₂2⁶ = 6log₂2 = 6

Тогда: (log₃81) ⋅ (log₂64) = 4 ⋅ 6 = 24

Ответ: 24