jika log2=a dan log3=b,maka nilai log 120=

log 2 = a
log 3 = b
log 120 = log ( 2³ x 3 x 5 )
= 3log2 + log3 + log5
= 3a + b + log(10/2)
= 3a + b + (1 - a)
= 2a + b + 1