The domain of a function is the set of values of x for which the function can be evaluated.
For a rational function like this (a fraction with variables in the numerator and denominator), the domain is all values EXCEPT any that make the denominator 0, because division by 0 is not allowed.
For this function, the only value that makes the denominator 0 is x=2, so the domain of the function is all real numbers except 2.
In algebraic notation:
In interval notation: (-infinity, 2) U (2, infinity)
