The function `f(x)` has a domain of "all real numbers, `x > 2`" as defined in the question. (There are no resulting square roots of negative numbers or divisions by zero involved here.)

To find the range:

Hence, the range is "all real numbers, `f(x) > 8`"

Here is the graph of the function, with an open circle at `(2, 8)` indicating that the domain does not include `x = 2` and the range does not include `f(2) = 8`.

1 2 3 4 5 6 5 10 15 20 25 x f(x) (2, 8)
Domain: All `x>2`
Range:
All `f(x) > 8`

The function is part of a parabola. [See more on parabola.]