Jika diketahui 3log2= a dan 2log5 = b maka 3log40??

³log 40 = ³log (8×5)
= ³log 8 + ³log 5
= ³ log 2³ + ³ log 2. ²log 5
=3 .³log 2 + ab
=3a+ ab
= a (3+b)

³log2 = a
²log5 = b
³log40 = log40/log3
= ²log40/²log3
= ²log (5*8)/²log3
= ²log5 + ²log8 / ²log3
= b + ²log2³ / 1/a
= b + 3.²log2 / 1/a
= b + 3 / 1/a
= (b + 3) * a
= ab + 3a