log(√3) ∛81=log(3¹/²) ∛3⁴=2*log₃ 3⁴/³=(2*4/3)log₃3=8/3.
log₁/₅25=log(5⁻¹) 5²=-log₅5²=-2*log₅5=-2.
log₂(lg10000)=log₂(lg10⁴)=log₂(4*lg10)=log₂4=log₂2²=2*log₂2=2.
log(√3) ∛81=log(3¹/²) ∛3⁴=2*log₃ 3⁴/³=(2*4/3)log₃3=8/3.
log₁/₅25=log(5⁻¹) 5²=-log₅5²=-2*log₅5=-2.
log₂(lg10000)=log₂(lg10⁴)=log₂(4*lg10)=log₂4=log₂2²=2*log₂2=2.