Answer:
Explanation:
The trouble maker is √(x - 3).
If you try and put in (say) - 1 for x, what happens is that you are taking the square root of -1 - 3 = - 4. At this level of math, you can't take the square root of a number < 3. So that modified is what you put in the blank.
The domain for f(x) is all the real numbers larger than or equal to 3.