1. -log 7 36-log 7 14-3 log 7 √21 = ?

-log_7 36 - log_7 14 - 3 log_7 \sqrt{21} = -log_7 (36 \times 14) - log_7 (\sqrt{21})^3 = -log_7 (504) - log_7 (21^{3/2}) = -log_7 (504) - log_7 (21 \sqrt{21}) = -log_7 (504 \times 21 \sqrt{21}) = -log_7 (10584 \sqrt{21})