4 1499. a) log3 7-log39; 2 1 B) logi+log 72 12 2

1499. Вычислите:

а) $$log_3 7 - log_3 9 = log_3 \frac{7}{9}$$

б) $$log_{\frac{1}{12}} \frac{1}{2} + log_{\frac{1}{12}} 72 = log_{\frac{1}{12}} (\frac{1}{2} \cdot 72) = log_{\frac{1}{12}} 36$$

$$log_{\frac{1}{12}} 36 = log_{\frac{1}{12}} (\frac{1}{12})^{-log_{\frac{1}{12}} (\frac{1}{12})} 36 = -log_{\frac{1}{12}} 36 $$

Ответ: a) $$log_3 \frac{7}{9}$$, б) $$log_{\frac{1}{12}} 36$$