Concept:Use the logarithm quotient rule: loga(nm)=logam−logan.Explanation:Write 5 as 210.So, log105=log10(210).Apply the quotient rule:log105=log1010−log102.Since log1010=1 and log102=0.3010,log105=1−0.3010=0.6990.Answer:log105=0.6990.