Answer
$\color{blue}{(-\infty, 6) \cup (6, +\infty)}$
Work Step by Step
The denominator of a rational expression is not allowed to be equal to zero as it will make the expression undefined.
Thus,
$x-6 \ne 0
\\x-6+6\ne0+6
\\x\ne 6$
The value of $x$ can be any real number except $6$.
Therefore, the domain of the given rational expression is the set of real numbers except $6$.
In interval notation, the domain is:
$\color{blue}{(-\infty, 6) \cup (6, +\infty)}$
