From the description, we have the function 
Since the square root cannot be a negative number, the only thing need to do to find the domain of the function
is take the expression inside the square rot and set it greater or equal than zero:
or 
We can conclude that we can use the inequality
to find the domain of . Also, the domain of is (∞,
]U(5,∞).
Since the square root cannot be a negative number, the only thing need to do to find the domain of the function
We can conclude that we can use the inequality