Answer:
1. Yes, is a function {(2, 2),(4, 4),(6, 6),(8, 8)}
2. Yes, is a function {(0, 3),(3, 5),(5, 6),(8, 4)}
3. Yes, is a function {(1, 2),(3, 3),(4, 8),(6, 3)}
4. No, not a function {(3, 4),(5, 2),(5, 6),(7, 3)}
Explanation:
1. Since there is one value of y for every value of x in {(2, 2),(4, 4),(6, 6),(8, 8)} , this relation is a function.
2. Since there is one value of y for every value of x in {(0, 3),(3, 5),(5, 6),(8, 4)}, this relation is a function.
3. Since there is one value of y for every value of x in {(1, 2),(3, 3),(4, 8),(6, 3)}, this relation is a function.
4. Since x=5 produces y=2 and y=6, the relation {(3, 4),(5, 2),(5, 6),(7, 3)}, is not a function.