:))))))

8. Domain = All possible X values and Range = All possible y values (withouth duplicates. Can you calculate it now with the given points?

9. Same as #8

10. Remove duplicates, you'll be good to go with #8.

11. Also #8

12. Sometimes. All functions are relations, but not all relations are functions, by the vertical line test.

13. Graph the points. Next, determine if any two x coordinates are the same. If they are, it's a no for being a function. If they aren't then yes.

14. Follow #13

15. Follow #13, or just look at the x and y coordinates.

16. Are any x coordinates the same? (#13 again)

17.

a) We must not have the same x coordinate, by the vertical line test. So, because age is the x coordinate, age cannot go down, so it must be a function!

b) Probably not, unless the person is super healthy. The reasoning behind this is that as the age goes higher, the old person's might get shorter and thus the graph will have overlapping x coordinates, as you must have reached a certain point to regress back to it, as the word implies.

18. No, as there are two values for y when x = -1.

19. Yes, by the vertical line test.

20. No, as there are two values for y when x = 1 or 2.