I wanted to double check my work. I am trying to find the domain:

Question

1. f(x)= x+5
Answer: No Domain

2. f(x) = 1
X+5
Work: x+5≠0
X=-5
Answer: (-∞,-5) ᴜ (-5,∞)

3. f(x)= √x+2
Work: x+2 ≥ 0
x ≥ -2
Answer: [-2,∞)

Answer 1

#1 EVERY function has a domain. A function is a relation between two sets: the domain and the range.
The domain of any polynomial function is all real numbers.

#2 If you mean f(x) = 1/(x+5), then you are correct (except you meant x ≠ -5)

#3 correct
If you meant √(x+2)