(x₁,y₁) = (2,-3)
(x₂,y₂) = (2,9)
To determine the slope using two points lie on the line, we could use the following formula
m = [tex] \dfrac{y_{2}-y_{1}}{x_{2}-x_{1}}[/tex]
plug in the numbers
m = [tex] \dfrac{9-(-3)}{2-2} [/tex]
m = [tex] \dfrac{9+3}{0} [/tex]
m = [tex] \dfrac{12}{0} [/tex]
m = undefined
The slope is undefined, the line is vertical
