diketahui 2 log 7 = A dan 2 log 3 = b maka nilai dari 9 log 21 =

jawab

²log 7 = a
²log 3 = b

⁹log 21 = ²log 21/ ²log 9

= (²log 7. + ²log 3) / (²log 3²)
=  (a + b) /(2b)

==Jawaban==

²log7 = a
²log3 = b


Maka,,
⁹log21
= ²log21 : ²log9
= ²log(7.3) : ²log3²
= ²log7 + ²log3 : 2.²log3
= a + b : 2.b
= (a + b)/2b