Answer:
∞ or undefined
Explanation:
The slope of a line that passes through two points A(x₁,y₁) and B( x₂,y₂) is found by finding the ratio of the change in y (y₂-y₁) to the change in x (x₂-x₁)
Thus the provided line has a slope of:
(13-⁻8)/(4-4)= 21/0
= ∞
This is a vertically perpendicular line through x=4