How is the slope of a line calculated using two points?

To calculate the slope of a line using two points, the formula used is the change in the y-coordinates divided by the change in the x-coordinates. This is expressed mathematically as the difference between the y-values of the two points (y2 and y1) over the difference between the x-values (x2 and x1). Therefore, the correct formula for finding the slope is:

Slope = (y2 - y1) / (x2 - x1)

This formula works because slope represents how steep a line is and in what direction it rises or falls. If you think of it graphically, the 'rise' of the line is the vertical distance between the two points, while the 'run' is the horizontal distance. By calculating the ratio of these two distances, you get a clear numeric value representing the slope.

Other options do not represent the correct method for calculating slope. For instance, calculating with additions or using the coordinates in the format that involves summation does not provide the necessary differences needed to determine the directional change of the line. Hence, only the correct formula reflects the relationship between the x and y changes effectively.