Answer:
See answers below.
Step-by-step explanation:
A relation is a function if the x-value in group of ordered pairs is only used one time.
1. Not a function: The x-value 4 was used twice.
2. Yes, it is a function: Each x-value was used one time.
3. Not a function: The x-value -2 was used twice.
4. Yes, it is a function: Each x-value was used one time.
5. Not a function: Each x-value -1 and -2 were used twice.
6. Not a function: The x-value 1/2 was used twice (1/2, 0) and (1/2, 1).
