sederhanakan bentuk berikut 3 log 5 + log 8 - log 40

= 3 log 5 + log (8/40)
= 3 log 5 + log 1/5
= 3 log 5 + log 5^-1
= log 5^3 + log 5^-1
= log (5^3 x 5^-1)
= log 5²
= 2 log 5