Calculate the slope of a line using two different pairs of points

Take P(x1,y1) and P(x2,y2)

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

y-y1=m (x-x1) is the actual line

Note, you can choose either of the two points to be (x1,y1) and (x2,y2)

Calculus shows that functions have slopes as well which can be evaluated at any given point as long as it is continuous

Let the two different pairs of the points be:

(x₁, y₁) and (x₂, y₂)

Slope = Change in y / Change in x =  (y₂ - y₁) / (x₂ - x₁)

Hence Slope =   (y₂ - y₁) / (x₂ - x₁)

A