Given:
The logarithmic expression is:
[tex]\log_718[/tex]
To find:
The equivalent expression of given expression by using change-of-base formula.
Solution:
The change-of-base formula is:
[tex]\log_ba=\dfrac{\log_ca}{\log_cb}[/tex]
The given expression is:
[tex]\log_718[/tex]
Using the change-of-base formula, we get
[tex]\log_718=\dfrac{\log_c18}{\log_c7}[/tex]
Where, is a constant and c>0.
Let [tex]c=10[/tex], then
[tex]\log_718=\dfrac{\log_{10}18}{\log_{10}7}[/tex]
Therefore, the correct option is a.
