в) Используем свойство логарифмов: $$a \cdot log_b c = log_b c^a$$ и $$log_b c + log_b d = log_b (c \cdot d)$$.
$$4 log_{12} 2 + 2 log_{12} 3 = log_{12} 2^4 + log_{12} 3^2 = log_{12} 16 + log_{12} 9 = log_{12} (16 \cdot 9) = log_{12} 144 = log_{12} 12^2 = 2$$
Ответ: 2