Log 8 (log16 (log5 25))

Log₈ (log₁₆ (log₅25)) = log₈ (log₁₆ 2) = log₈ (1/4 * log₂ 2) = 1/3 * log₂ 2⁻² = 1/3 * (-2) = - 2/3

использовали, что log₅25 = log₅ 5² = 2

log₁₆ 2 = log₂⁴ 2 = 1/4 log₂ 2 = 1/4 * 1 = 1/4

log₈ (1/4) = log₂³ (1/2) ²=1/3 * log₂ (2) ⁻² = 1/3 * (-2) = - 2/3