Question

The coordinates of point D are (7, 4) and the coordinates of point E are (1, −3) . What is the slope of the line that is perpendicular to DE¯¯¯¯¯?
Enter your answer as a simplified fraction.

Answer 1

The slope of a line is given by the change in y coordinates over the change in x coordinate.
The slope of line DE will be (4 - -3)/ (7-1) = 7/6
If M1 and M2 are slopes of two perpendicular lines at a point then
 M1× M2 = -1
 Thus, the slope of a perpendicular to line DE will be -6/7.