Which equation would you use to find the slope of a line between two points (x1, y1) and (x2, y2)?

To determine the slope of a line between two points, you need to understand what slope represents. The slope is a measure of the steepness of a line and is defined as the change in the vertical coordinate (y-coordinates) divided by the change in the horizontal coordinate (x-coordinates) between two points.

When considering two points represented as (x1, y1) and (x2, y2), the change in y (the vertical change) is calculated as (y2 - y1), which represents how much y changes when moving from the first point to the second. Similarly, the change in x (the horizontal change) is expressed as (x2 - x1), showing how much x changes between the two points.

Thus, the formula for slope is derived from these changes, leading to the expression (y2 - y1) / (x2 - x1). This correctly represents the ratio of the vertical change to the horizontal change, giving you the slope of the line connecting the two points.

In contrast, the other choices do not accurately represent the slope in the context of the standard definition, either inverting the necessary relationship or failing to reflect the concept of change correctly. Therefore, the first choice is