Answer:
- Is a function
- Isn't a function
- Is a function
- Isn't a function
Step-by-step explanation:
Firs we need to understand what is a function-
from a set [tex]X[/tex] to a set [tex]Y[/tex] is an assignment of an element of [tex]Y[/tex] to each element of [tex]X[/tex].
This mean's that an element in [tex]X[/tex] can't have multiples values in [tex]Y[/tex], then if you find a coordinate with two different values, isn't a function.
Take for example the second data set:
[tex]\{(2, 3), (2, 5), (3,6), (9,4)\}[/tex]
All is good except for the first two coordinates because [tex]x[/tex] is define with two different values, then you can determinate that isn't a function.
Maybe you're confuses because exist some graphs that repeat values in [tex]x[/tex] as the graph of a circle, but this in reality isn't a function, is a relation. A relation can repeat values in the set [tex]X[/tex] infinity times but never is going to be a function.
