Answer:
3 ≤ x ≤ 7 or x is between 3 and 7, inclusive
Step-by-step explanation:
Eira's graph probably resembled the diagram below.
The domain is the set of all possible x-values that will make a function work.
x can take any value from 3 to 7.
The domain is [3, 7] or 3 ≤ x ≤ 7.
Answer:

Step-by-step explanation:

20 can be written as a product of 4 and 5.

4 is a perfect square.

Square root of 4 is 2.
