Bila ³log2=1 dan ³log5=b maka 6log30=

'6 log30 = log30 / log6
= (log(2 . 3 . 5))/(log(2 . 3))
= (log2 + log3 + log5) /(log2 + log3)
= ('3 log2 + '3 log3 + '3 log5) /('3 log2 + '3 log3)
= (1 + 1 + b)/(1 + 1)
= (2 + b) /2