2. Which of the following relations are functions?

A) (-1, 3), (-4, 3), (-2, 3), (0, 3)
B) (8, 2), (6, -5), (7, -1), (6, 5)
C) (2, 4), (2, 7), (2, -1), (2, 0)
D) (8, 2), (6, 5), (7, -1), (6, 5)

3. Read the given scenarios. Determine if it is a function or not a function.
Function Not a Function
A) Input is Student ID number. Output is student age.
B) The teacher surveys the class. The input is the ages of students in class. The output is the grade level of students in class.
C) Input is the year a group of students graduates from high school. Output is a list of their current salaries.
D) Input is your birthday. Output is number of TVs in your house.

1 answer

Question 2: Which of the following relations are functions?

To determine if a relation is a function, each input (the first element of the ordered pairs) must correspond to exactly one output (the second element of the ordered pairs).

A) (-1, 3), (-4, 3), (-2, 3), (0, 3)

  • Inputs: -1, -4, -2, 0
  • Each input corresponds to a unique output (3).
  • This is a function.

B) (8, 2), (6, -5), (7, -1), (6, 5)

  • Inputs: 8, 6, 7, 6
  • The input 6 corresponds to two outputs (-5 and 5).
  • This is not a function.

C) (2, 4), (2, 7), (2, -1), (2, 0)

  • Inputs: 2, 2, 2, 2
  • The input 2 corresponds to multiple outputs (4, 7, -1, 0).
  • This is not a function.

D) (8, 2), (6, 5), (7, -1), (6, 5)

  • Inputs: 8, 6, 7, 6
  • The input 6 corresponds to one unique output (5), but the input 6 appears twice with the same output.
  • This is a function.

Summary for Question 2:

A is a function, B is not a function, C is not a function, D is a function.


Question 3: Read the given scenarios. Determine if it is a function or not a function.

A function must have a unique output for each input.

A) Input is Student ID number. Output is student age.

  • Each student ID corresponds to one unique student age.
  • This is a function.

B) The teacher surveys the class. The input is the ages of students in class. The output is the grade level of students in class.

  • Different students of the same age may be in different grade levels.
  • This is not a function.

C) Input is the year a group of students graduates from high school. Output is a list of their current salaries.

  • Multiple groups graduating in the same year can have different salaries.
  • This is not a function.

D) Input is your birthday. Output is number of TVs in your house.

  • A person's birthday does not uniquely determine the number of TVs in their house.
  • This is not a function.

Summary for Question 3:

A is a function, B is not a function, C is not a function, D is not a function.