Answer: The first relationship is a function.
Step-by-step explanation:
A relation is said to be a function if for each input value ( independent variable) there exist only one unique output value ( dependent variable).
- In first one , each output value is unique to each input value , hence it is a function.
- In second one ( teachers and their pets), where as pets are denoted as dependent variable ( since pets depends on their owners).
Here teachers are denoted as independent variable
Mrs. Valverde has two pets , i.e. there are two output values corresponds to one input value, hence it is not a function., so by definitin
- In third one, the first input value( yellow square) corresponds to two different outputs( square and triangle) , so by definition of function , this relation cannot be a function.
- In fourth one, 7 corresponds to two different outputs ( 12 and 13) , so by definition of function , this relation cannot be a function.
After observing all of the options , we can say that , the correct option is first one.
i.e. The first relationship is a function.