The approximate value of x in the equation using change of the base of logarithmic rule found as -1.317.
The change of base rule of the log is used to write the given logarithmic number in terms of ratio of two log numbers.
For example,
[tex]\log_ba=\dfrac{\log_xa}{\log_xb}[/tex]
Here, a,b is the real number and x is the base.
The logarithmic equation given in the problem is,
[tex]log_5(15) = x+ 3[/tex]
Using the change of base formula, the above equation can be written as,
[tex]\dfrac{log{15} }{log{5} }= x+ 3[/tex]
Isolate the x variable as,
[tex]x=\dfrac{log{15} }{log{5} }- 3\\x=\dfrac{1.17609}{0.69897}- 3\\x\cong-1.317[/tex]
Hence, the approximate value of x in the equation using change of the base of logarithmic rule found as -1.317.
Learn more about the rules of logarithmic function here;
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