Elementary and Intermediate Algebra: Concepts & Applications (6th Edition)

$3$
Using $\log_bx^m=m\log_bx$ or the Power Rule of Logarithms, the given expression, $\log_{5}125 ,$ is equivalent to \begin{array}{l}\require{cancel} \log_{5}5^3 \\\\= 3\log_{5}5 .\end{array} Since $\log_bb=1,$ the expression, $3\log_{5}5 ,$ simplifies to \begin{array}{l}\require{cancel} 3(1) \\\\= 3 .\end{array}