3 log 4 =a 4 log 5 = b Maka 12 log 125 adalah...

12 log 125
= kita balik menjadi
125 log 12
125 log 3 + 125 log 4

dari pertanyaan didapatkan
-3 log 4 x 4 log 5 = ab
3 log 5 = ab
maka, 5 log 3 = 1/ab

- 4 log 5 = b
5 log 4 = 1/b

125 log 3 + 125 log 4
5^3 log 3 + 5^3 log 4
(1/3) 5 log 3 + (1/3) 5 log 4
( 1/3 x 1/ab ) + ( 1/3 + 1/b )
= 1/3ab + 1/3b
=1/3ab + a/3ab
=a+1 / 3ab