Answer:
A function is a relation that maps elements from one set (the domain, the set of the inputs) into elements from another set (the range, the set of the outputs). Such that each element of the domain can be mapped into only one element of the range.
Now let's analyze the given relations.
1)
Here we can see that the inputs are -3, -1, 1, and 2.
Then the domain (the set of the inputs) is:
D = {-3, -1, 1, 2}
And we can see that the outputs are 0, 2, and 5.
Then the range is:
R = {0, 2, 5}
We also can see that each input is being mapped into only one output, then this relation is a function.
2) In this case the inputs are -2, -3, and 5.
Then the domain is:
D = {-2, -3, 5}
And the outputs are 6, 7, 8
Then the range is:
R = {6, 7, 8}
And we can see that each input is mapped into only one output, then this relation is a function.
3) In this case we can see that the inputs are -4, -2, and 0
Then the domain is:
D = {-4, -2, 0}
And we can see that the outputs are -2, -1, 3, and 4.
Then the range is:
R = {-2, -1, 3, 4}
In this case, we can see that the input -4 is being mapped into two different outputs (3 and -1)
Then this relation is not a function.