Questions: Find the domain of the following rational function.
R(x) = 12x / (x+9)
Transcript text: Find the domain of the following rational function.
\[
R(x)=\frac{12 x}{x+9}
\]
Solution
Solution Steps
To find the domain of the rational function \( R(x) = \frac{12x}{x+9} \), we need to determine the values of \( x \) for which the function is defined. The function is undefined when the denominator is zero. Therefore, we need to find the values of \( x \) that make the denominator zero and exclude them from the domain.
Step 1: Identify the Function
We are given the rational function
\[
R(x) = \frac{12x}{x + 9}.
\]
Step 2: Determine the Denominator
The function is undefined when the denominator is zero. Thus, we set the denominator equal to zero:
\[
x + 9 = 0.
\]
Step 3: Solve for Undefined Points
Solving the equation gives:
\[
x = -9.
\]
This means the function is undefined at \( x = -9 \).
Step 4: Define the Domain
The domain of the function consists of all real numbers except the point where the function is undefined. Therefore, the domain can be expressed as:
\[
\text{Domain} = (-\infty, -9) \cup (-9, \infty).
\]
Final Answer
The domain of the function \( R(x) \) is
\[
\boxed{(-\infty, -9) \cup (-9, \infty)}.
\]