To represent Elena's heart rate of 80 beats per minute on a graph, choose a scale of 1 unit per minute on the x-axis and 20 units per beat on the y-axis. The slope of Elena's line is 0.
To create a scale for the x and y axis that represents Elena's heart rate of 80 beats per minute, we can choose a suitable interval for both axes. For the x-axis, we can choose a scale of 1 unit per minute. For the y-axis, we can choose a scale of 20 units per beat.
This means that each unit on the x-axis represents 1 minute, and each unit on the y-axis represents 20 beats. Therefore, if we plot a point at (1, 20), (2, 40), (3, 60), and so on, we will be able to represent Elena's heart rate of 80 beats per minute on the graph.
The slope of Elena's line can be determined by finding the change in y divided by the change in x for any two points on the line. In this case, since the heart rate is constant at 80 beats per minute, the change in y is 0 for any two points. Therefore, the slope of Elena's line is 0.