Question

which of these relations is a function?

Explanation:

Step1: Recall function test rule

A relation is a function if every vertical line intersects its graph at most once (Vertical Line Test).

Step2: Test top-left graph

There exists a vertical line that crosses this graph twice, so it is not a function.

Step3: Test top-right graph

Every vertical line crosses this graph at most once, so it passes the test.

Step4: Test bottom-left graph

A vertical line can cross the circle twice, so it is not a function.

Step5: Test bottom-right graph

A vertical line can cross this parabola twice, so it is not a function.

Answer:

The top-right S-shaped graph (the relation in the top-right grid) is a function.