Question

Which statement best illustrates using the vertical line test to determine if the graph below is a function of x ?

A) the graph is not a function of x because the line x = 0 intersects the graph at two points.
B) the graph is a function of x because the line x = 5 does not intersect the graph
C) the graph is not a function of x because the line y = 0 intersects the graph at two points
D) The graph is a function of x because the line y = 5 does not intersect the graph

Answer 1

If something is a function, every x-value, only has one (1) y-value. If the line x = 0 intersects the graph in two points, there are to values for y (instead of one). Therefore the graph is not a function of x.

Your answer is A.

Answer 2

A

Explanation:

A function can only have one output value "y" for each input "x", so if a vertical line in an xy plane (therefor the line test) that you can imagine, or you can see by using a ruler intersects more than one point on the same line, you have more than one value for x, and that is not a function.

as you see in option A, the line x=0 intersects the graph at two points.