Jika log 2 = a dan log 3 = b, nilai log 120 =

log120 = log(40*3)
= log40 + log3
= log(20*2) + b
= log(20) + log2 + b
= log(2*10) + a + b
= log2 + log10 + a + b
= a + 1 + a + b
= 2a + b + 1

semoga membantu :)