Step-by-step explanation:
To find the slope of a line given two points we use the formula
[tex]m = \frac{ y_2 - y _ 1}{x_ 2 - x_ 1} [/tex]
where
(x1 , y1) and (x2 , y2) are the points
From the question the points are
(4,2) and (4,-6)
The slope is
[tex]m = \frac{ - 6 - 2 }{4 - 4} = - \frac{8}{0} [/tex]
Hope this helps you