Вычислим 2log46 + log4(5/9) - log45
2log46 + log4(5/9) - log45 = log462 + log4(5/9) - log45 = log436 + log4(5/9) - log45 = log4(36 * (5/9) / 5) = log4(36 * 5 / (9 * 5)) = log4(36/9) = log44 = 1
Ответ: 1