Найти значение выражения 6log279 - 2. log31/3

Воспользуемся свойствами логарифмов:

loga^b (c) = (1/b) * loga (c),

loga (b^c) = c * loga (b)

и

loga (a) = 1:

6 * log27 (9) - 2 * log3 (1/3) =

= 6 * log3^3 (3^2) - 2 * log3 (3^-1) =

= 6 * (1/3) * log3 (3^2) - 2 * (-1) * log3 (3) =

= 2 * 2 * log3 (3) + 2 =

= 4 + 2 = 6.