Answer:
slope is undefined
Step-by-step explanation:
calculate the slope m using the slope formula
m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
with (x₁, y₁ ) = (6, 4 ) and (x₂, y₂ ) = (6, - 2 )
m = [tex]\frac{-2-4}{6-6}[/tex] = [tex]\frac{-6}{0}[/tex]
division by zero is undefined, therefore the slope of the vertical line is undefined.