The definition of the slope can be interpreted by the following formula.
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]selcect two points from the graph
(0,-2)
(0,-4)
replace the points into the formula
[tex]\begin{gathered} m=\frac{(-4)-(-2)}{0-0} \\ m=\frac{-4+2}{0} \\ m=\frac{-2}{0} \\ m=\text{IND} \end{gathered}[/tex]Since any number divided by 0 is indetermined, the slope of the line is undefined.
