YOU HAVE TO FIND THE SLOPE m
The formula to find the slope is m=(y₂-y₁)/(x₂-x₁)
Since we have the coordinate of each point, then we can calculate the slope m
7) (-6-3)/(2+4) = -9/6 =-3/2 (slope negative so the function falls
8) (-1-1)/(7-7) = -2/0 (tan ---> ∞ ) VERTICAL
9) (-2+2)/(5-3) = 0/2 = 0 slope = 0 ===> Horizontal
