Hello!
The function f/g means that that f(x) is written in the numerator and g(x) is written in the denominator because we are dividing the functions f(x) and g(x). (f/g = f(x)/g(x))
f(x)/g(x) is shown as: (3x - 6)/(x - 2).
The function shown above can be factored before we find the domain, since the greatest common factor of the numerator is 3.
f(x)/g(x) = 3(x - 2)/(x - 2)
f(x)/g(x) = 3
The function y = 3 is a horizontal line, so it has a domain of all real numbers.
Therefore, f/g is 3, and its domain is all real numbers, which is choice D.