Find the domain of [tex]$f(x)=\frac{7x}{x-3}$[/tex].

A. All real numbers except 3
B. All real numbers except 7
C. All real numbers except 0
D. All real numbers except -3



Answer :

To find the domain of the function [tex]\( f(x) = \frac{7x}{x-3} \)[/tex], we need to determine the values of [tex]\( x \)[/tex] that make the function undefined. This function is a rational function, and rational functions are undefined where the denominator is zero.

Here are the steps to solve this problem in detail:

1. Identify the Denominator:
The denominator of the given function is [tex]\( x - 3 \)[/tex].

2. Set the Denominator Equal to Zero:
To find the values that make the function undefined, set the denominator equal to zero:
[tex]\[ x - 3 = 0 \][/tex]

3. Solve for [tex]\( x \)[/tex]:
Solving the equation [tex]\( x - 3 = 0 \)[/tex] gives:
[tex]\[ x = 3 \][/tex]

4. Determine the Domain:
Since the function is undefined when [tex]\( x = 3 \)[/tex], the domain of [tex]\( f(x) = \frac{7x}{x-3} \)[/tex] includes all real numbers except [tex]\( x = 3 \)[/tex].

Hence, the domain of [tex]\( f(x) \)[/tex] is all real numbers except [tex]\( 3 \)[/tex].

Therefore, the correct answer is:
All real numbers except 3.