Question

Which of the following best describes when a relation is a function?

O A. Each element in the domain is the same as each element in the
range.
O B. Each element in the domain is twice the size of each element in
the range.
C. Each element in the domain is paired with just one element in the
range.
O D. Each element in the domain is paired with at least one element in
the range.

Answer 1

Explanation:

The answer is C.

That's another way of using the vertical line test. Put a ruler perpendicular to the x axis and going through a point. If the ruler hits only one point, then then if all the points plotted do the same thing, then the points make a function.

C says the same thing. Only 1 element in the domain (x) can be associated with 1 y value (the range). If there is more than 1 y value, then you do not have a function.