2 2  LOG 27 LOG 3 LOG 1612 2 6  LOG 12 2 LOG 3 3 3A A

Câu 56.

Ta có:

2

2

 

log 27

log 3

log 16

12

2

6

log 12

2 log 3

3

3

a

a

.

2

2

lg30

1 lg3

1

a