Question

If ${\log }_5(x-7)=1$, then value of $x$ is equal to

• A. $12$
• B. $13$
• C. $14$
• D. $15$

Answer 1

The correct option is A $12$

${\log }_5(x-7)=1$

$\therefore \frac{\log (x-7)}{\log 5}=1$ ....(${\log }_{b}a=\frac{\log a}{\log b}$)

$\therefore \log (x-7)=\log 5$

$\therefore x-7=5$

$\therefore x=12$