Answer :

Sure, let's solve the given expression step by step:

Given expression:
[tex]$ \frac{9-4}{78,942}-18 $[/tex]

1. Start by simplifying the numerator:
[tex]$ 9 - 4 = 5 $[/tex]

2. Now, substitute the simplified numerator back into the expression:
[tex]$ \frac{5}{78,942} - 18 $[/tex]

3. Perform the division:
[tex]$ \frac{5}{78,942} \approx 6.333764029287325 \times 10^{-5} $[/tex]

4. Subtract 18 from the result of the division:
[tex]$ 6.333764029287325 \times 10^{-5} - 18 \approx -17.99993666235971 $[/tex]

5. Round the final result to 3 decimal places:
[tex]$ -17.99993666235971 \approx -18.0 $[/tex]

So, the rounded answer to 3 decimal places is:
[tex]$ \boxed{-18.0} $[/tex]