Question

The value of the expression ${\log }_{8}512+\left[\frac{\log 7+\log 42-\log 6}{\log 49}\right]$ is

Answer 1

${\log }_{8}512+\left[\frac{\log 7+\log 42-\log 6}{\log 49}\right]$
$={\log }_8{8}^3+\left[\frac{\log \left(\frac{7\times 42}{6}\right)}{\log 49}\right]$
$=3+\left[\frac{\log 49}{\log 49}\right]$
$=3+1=4$