Question 322023
The domain is all values that x can take on. The only problem I have with this function is that I cannot have a negative inside the square root. So I'll set the insides greater-than-or-equal-to zero, and solve. The result will be my domain:

4 - x ≥ 0

- x ≥ 0 - 4

-x ≥ -4

x ≤ -4/-1

x ≤ 4

The values for x must be less than or equal to 4.  Anything else will make the square root function undefined.