Now, what can we do with this solution set? We can plot the individual pairs as points on a graph as shown below.
Take the x value chosen. This represents the distance of the point from the y-axis.
The resulting y-value represents the distance of the point from the x-axis.
For example, when x equals 1, y equals 11. Thus we have a point : one, eleven, as shown.
Next, when x = -1, we have y=5.
As we plot more and more points like this based on the x and y values, we end up with the following set of points. There are an unlimited number of points we can plot like this. What does this look like?
It is a straight line. We say that the equation represents a straight line on the graph.
Not only do all the pairs of values in the solution set of the equation correspond to a point on the line but also, EVERY point on the line in the graph corresponds to an x and a y value that satisfies the equation in 2 variables.