I have to explain the vertical line test and how it is used.

See:

http://en.wikipedia.org/wiki/Vertical_line_test

If you need further explanations, please post.

Have to explain how to use a graph to determine the number of solutions system.

Am lost on what they want.

There was a response for you in case you did not check back:

http://www.jiskha.com/display.cgi?id=1299626093

The vertical line test is a method used in mathematics to determine whether a graph represents a function. It helps us identify whether there is a unique output for every input in the given graph.

To explain the vertical line test, you can follow these steps:

1. Draw an imaginary vertical line anywhere on the graph. This line can be positioned at any x-coordinate.

2. Observe the points where the vertical line intersects the graph. If the line only intersects the graph at one point for each x-coordinate, then the graph represents a function.

3. However, if the vertical line intersects the graph at multiple points for any x-coordinate, then the graph does not pass the vertical line test and does not represent a function.

To summarize, the vertical line test is useful for determining whether a graph represents a function or not by checking if there is a unique output for each input. By drawing imaginary vertical lines and observing the points of intersection with the graph, we can easily identify if the given graph passes the test or not.