What is the slope of the line joining the points (x1,y1) and (x2,y2)?
The slope of a line joining the points (x1,y1) and (x2,y2) is y1−y2x1−x2.
Midpoint of the line joining the points (x1,y1) and (x2,y2) is (x1+x22,y1+y22).