40. loga + log,a² log81a

40. (loga + log√3a²)/log₈₁a = (loga + 2log√3a)/log₈₁a = (loga + 2loga/logₐ√3)/loga/logₐ81 = loga(1 + 2/logₐ√3)·logₐ81/loga = (1 + 2/(1/2logₐ3))·logₐ3⁴ = (1 + 4/logₐ3)·4logₐ3 = 4logₐ3 + 16

Ответ: 4logₐ3 + 16