Question

Evaluate  the following without using tables : 
log 5 + log 8 - 2 log 2

Answer 1

Consider the given expression
log 5 + log 8 - 2 log 2        .....[ nlog_am = log_amⁿ ]
= log 5 + log 8 x 8 - log 2² ......[ nlog_am = log_amⁿ ]
= log 5 x 8 - log 2²
= log 40 - log 4

= log`40/4`                          .....[ log_am - log_an = log_a`(m/n)`]
= log 10 
= 1