## Precalculus (6th Edition)

$\color{blue}{(-\infty, 6) \cup (6, +\infty)}$
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: $\color{blue}{(-\infty, 6) \cup (6, +\infty)}$