http://www.tractordata.com/threepoint.html
(1,4)Let (x,y) represent the point of reflection. We know that A and A' must be on the same line as (x,y) and must be equidistant from (x,y).Because they are equidistant from (x,y), we...
it would be the mixed number 1 and 3/10
m=y2-y1/x2-x1 m=-1- 3/3-(-3) m=-4/6 m=-2/3
5.4
39 :D