The domain of a function refers to the set of all values of the independent variable (usually denoted by x) for which the function is defined.
For the function f(x) = 2, the expression is defined for all real values of x. Therefore, the domain of f(x) is all real numbers.
If the function was f(x) = 2 / (x - 9), then the expression is undefined for x = 9. Therefore, the domain of f(x) would be all real numbers except 9.
If the function was f(x) = 2 / (x - 3)(x + 3), then the expression is undefined for x = 3 and x = -3. Therefore, the domain of f(x) would be all real numbers except 3 and -3.
If the function was f(x) = sqrt(2x - 5), then the expression is only defined for values of x that make the argument of the square root non-negative. Therefore, the domain of f(x) would be all real numbers such that 2x - 5 >= 0, which simplifies to x >= 5/2.
Therefore, without more information about the function, it is impossible to determine its domain.