To express the domain of the function $\frac{5}{x-3}$ in interval notation, we need to determine the set of all $x$-values for which the function is defined.

The function $\frac{5}{x-3}$ is undefined when the denominator $x-3$ equals zero. This occurs when $x = 3$. Therefore, the function is defined for all real numbers except $x = 3$.

The domain in interval notation is: $(-\infty, 3) \cup (3, \infty)$

This notation means that $x$ can be any real number except 3.

Would you like further explanation on this, or have any specific questions? Here are some related questions:

1. How do you solve inequalities involving rational functions?
2. What does the graph of $\frac{5}{x-3}$ look like?
3. How do you express the range of $\frac{5}{x-3}$ in interval notation?
4. How do you find the x-intercept of $\frac{5}{x-3}$?
5. What are some real-world applications of rational functions like $\frac{5}{x-3}$?

Tip: When finding the domain of a function, look for values that make the denominator zero or other undefined operations, such as square roots of negative numbers.