293 1) logg 12 - logg 15 + logg 20; 3 2) logg 15 + logg 18 – logg 10;

1) $$log_8 12 - log_8 15 + log_8 20 = log_8 \frac{12 \cdot 20}{15} = log_8 \frac{12 \cdot 4}{3} = log_8 (4 \cdot 4) = log_8 16 = log_8 8^{\frac{4}{3}} = \frac{4}{3}$$

2) $$log_9 15 + log_9 18 - log_9 10 = log_9 \frac{15 \cdot 18}{10} = log_9 \frac{3 \cdot 18}{2} = log_9 (3 \cdot 9) = log_9 27 = log_{3^2} 3^3 = \frac{3}{2} log_3 3 = \frac{3}{2}$$

Ответ: 4/3; 3/2