To find the slope ⇒ we must know the formula
Formula = [tex]\frac{y2-y1}{x2-x1}[/tex]
Now let's solve and plug the known variables
Slope = [tex]\frac{8-(-4)}{3-3} =\frac{12}{0}[/tex]
Nothing can be divided by zero
⇒ in this case, the slope is undefined
*interesting fact: the line is vertical
Hope that helps!