[tex]jika \: ^{2} log(3) = a \: dan \: ^{3} log(7) = b \: maka \: \frac{2 + ab}{1 + 2a} = [/tex]

²log 3 . ³log 7 = ab
²log 7 = ab

(2 + ab )/( 1  + 2a ) = (2 + ²log 7)/(1 + 2.²log 3)
= (²log 2² + ²log 7) /(²log 2 + ²log 3²)
= ( ²log 4 + ²log 7) /(²log 2 + ²log 9)
= ( ²log 28 ) /( ²log 18)
= ¹⁸log 28