Question

dados log 2=a, log 3=b e log 10=1 .Calcule log60

Answer 1

Observe 
log a + log b = log a*b 
============================== 

log 2 + log 3 + log 10= 1+a+b 

log 60=1+a+b

Answer 2

Observe 
log a + log b = log a*b 
============================== 

log= 2 + log= 3 + log= 10= 1+a+b +c

log 60=1+a+b