The video tutorial discusses how to determine if a graph represents a function using the vertical line test. The instructor explains that a graph is not a function if a vertical line intersects it at more than one point. The tutorial includes an analysis of four graphs, identifying which one does not pass the vertical line test, thus not being a function. The lesson concludes with a summary of the key points covered.

What is the vertical line test and how is it used to determine if a graph represents a function?

Explain why a graph that intersects a vertical line at more than one point is not considered a function.

Describe the process of using the vertical line test on a graph. What should you look for?

Identify the characteristics of a graph that is a function based on the vertical line test.

Based on the discussion, which choice was determined to be not a function and why?