The fromula of a slope:
[tex]m=\dfrac{y_2-y_1}{x_2-x_1}[/tex]
We have the points [tex]\left(\dfrac{2}{3},\ \dfrac{4}{7}\right)[/tex] and [tex]\left(\dfrac{2}{3},\ \dfrac{11}{7}\right)[/tex]
Substitute:
[tex]m=\dfrac{\frac{11}{7}-\frac{4}{7}}{\frac{2}{3}-\frac{2}{3}}=\dfrac{\frac{7}{7}}{0}\ !!!![/tex]
Answer: slope is undefined.
It's a vertical line: [tex]x=\dfrac{2}{3}[/tex]
