Question

Tell whether each of the following is a function.

Answer 1

Options A, C and D are functions.

In a function, for every number for 'x' there is only one 'y'. So, if you have two ordered pairs in a choice that have the same number for 'x', that is not a function.

Remember an ordered pair is written (x, y).

B is not a function as:
(x, y)
(1, -2)
(1, -3)
(1, -4)
^ All of the x-coordinates are the same.

E is not a function as:
(x, y)
(6, -1)
(6, -8)
^ Two of the x-coordinates are the same.

Thus, A, C and D are functions.