Iknow this isn't the subject of math, but nobody can answer it in math and i need with the steps because i need to turn it in i know the answer i just need with the steps and you! btw the correct answer is a

F(x)=-1/x
g(x)=√(3x-9)

Domain of (f/g)(x):  ??

1We find out the domain of f(x):
f(x) is a rational function, therefore can take real values if the denominator is not ("0"), therefore the domain of f, will be all values excpet "0"
Domain of  f: (-∞,0)U(0,+∞); 

                                                          o
O
← -∞                                                               +∞           →

g(x) is a radical square root  function, therefore the radicand have to be greater than o equal to "0"
3x-9≥0
3x≥9
x≥3

                                                         3
Ф
← - ∞                                                        +∞ →
          
(f/g)(x) = (-1/x) / (√(3x-9)) is a rational function with a square root in the denominator,also the square root don´t take the value of "0";
Therefore:
3x-9>0
3x>9
x>3

The domain of the function (f/g)(x) only can take the values found in all three domains at once.
                                                            3
0
← -∞                                                          +∞→

(3,+∞)