The first relation (10) is a function. Its domain is:
[tex]\lbrack-4,\infty)[/tex]And its range is:
[tex]\lbrack-2,\infty)[/tex]The second relation (11) is not a function. Its domain is the number -2 and its range are all the real numbers.
The third relation is a function. Its domain is:
[tex](-\infty,\infty)[/tex]Its range is the number 2.