Questions: Find the domain of the function.
f(x)=6-3 log8[(x/3)-7]
The domain of f is
(Type your answer in interval notation.)
Transcript text: Find the domain of the function.
\[
f(x)=6-3 \log _{8}\left[\frac{x}{3}-7\right]
\]
The domain of $f$ is $\square$
(Type your answer in interval notation.)
Solution
Solution Steps
To find the domain of the function \( f(x) = 6 - 3 \log_{8}\left[\frac{x}{3} - 7\right] \), we need to determine the values of \( x \) for which the argument of the logarithm is positive. The logarithm function is only defined for positive arguments. Therefore, we solve the inequality \(\frac{x}{3} - 7 > 0\).
To find the domain of the function \( f(x) = 6 - 3 \log_{8}\left[\frac{x}{3} - 7\right] \), we need to determine the values of \( x \) for which the logarithmic expression is defined.
Step 1: Determine the Condition for the Logarithm
The logarithmic function \(\log_{8}\left[\frac{x}{3} - 7\right]\) is defined only when the argument \(\frac{x}{3} - 7\) is positive. Therefore, we need to solve the inequality:
\[
\frac{x}{3} - 7 > 0
\]
Step 2: Solve the Inequality
To solve the inequality \(\frac{x}{3} - 7 > 0\), we perform the following steps:
Add 7 to both sides of the inequality:
\[
\frac{x}{3} > 7
\]
Multiply both sides by 3 to solve for \( x \):
\[
x > 21
\]
Step 3: Express the Domain in Interval Notation
The solution to the inequality \( x > 21 \) indicates that the domain of the function is all real numbers greater than 21. In interval notation, this is expressed as:
\[
(21, \infty)
\]
Final Answer
The domain of \( f \) is \(\boxed{(21, \infty)}\).