Question

Which graphs represent functions?

4
←
4
•
4
4 -2
++
Graph A
4
2
2
2
4
4
2 4
Graph C
X
-4
-2
4
-2
2
-2-
4
Graph B
у
4-
2
-2
Graph D
4
4

Answer 1

Answer is graphs B and D

Step-by-step explanation

We know the graph is a function if there is one output (y) for every input (x). We can also use the vertical line test to see if the line is crossed in more than one place.

Using the vertical line test I can see my vertical line will cross the line more than one time on Graph A meaning there is more than one output for every input. There is 2 points at x = 1, so there are more than one output for x=1 input.

Graph B and D pass the vertical line test and there are not more than one output for every input.

See the attachment.