Answer:
1. not a function.
2. is a function.
3. is a function.
4. not a function.
5. is a function.
6. not a function.
7. not a function.
8. is a function.
9. not a function.
10. is a function.
11. not a function.
12. not a function.
Explanation:
1. not a function because the same input goes to 2 different outputs. A function input cannot have 2 outputs.
2. is a function because each input only goes to one output.
3. is a function because each input only goes to one output.
4. not a function because the same input goes to 2 different outputs. A function input cannot have 2 outputs. It does not pass the vertical line test.
5. is a function because each input only goes to one output.
6. not a function because the same input goes to 2 different outputs. A function input cannot have 2 outputs.
7. not a function because the same input goes to 2 different outputs. A function input cannot have 2 outputs.
8. is a function because each input only goes to one output. It also passes the vertical line test.
9. not a function because the same input goes to 2 different outputs. A function input cannot have 2 outputs. It also did not pass the vertical line test.
10. is a function because each input only goes to one output. It also passes the vertical line test.
11. not a function because the same input goes to 2 different outputs. A function input cannot have 2 outputs. It also did not pass the vertical line test.
12. not a function because the same input goes to 2 different outputs. A function input cannot have 2 outputs. It also did not pass the vertical line test.
Hope this helps!