Question

Dik: 2log3 = a
3log7 = b
Tentukan nilai 21log48

Answer 1

^2 log 7 = ^2 log 3 . ^3 log 7 = ab

^21 log 48
= log 48 / log 21
= ^2 log 48 / ^2 log 21
= ^2 log (2^4 . 3) / ^2 log (3 . 7)
= (4 . ^2 log 2 + ^2 log 3) / (^2 log 3 + ^2 log 7)
= (4 . 1 + a) / (a + ab)
= (4 + a) / (a + ab)

Answer 2

^2log3 = a
log3/log2 = a
log3 = ^alog2

^3log7 = b 
log7/log3 = b
log7 = ^blog3 

Maka,
21log48
= log48/log21
= (log2^4.3)/(log3.7)
= (4 log2 + log3)/(log3 + log7)
= (4 log2 + a log2)/(a log 2 + b log3)
= (4 log2 + a log2)/(a log 2 + b a log 2)
= (4 + a)/(a + ba)
= (4 + a)/(a + ab)