Question

What is the slope if the line through the points 2/3, 4/7 and 2/3, 11/7

Answer 1

The fromula of a slope:

$m=\dfrac{y_2-y_1}{x_2-x_1}$

We have the points $\left(\dfrac{2}{3},\ \dfrac{4}{7}\right)$ and $\left(\dfrac{2}{3},\ \dfrac{11}{7}\right)$

Substitute:

$m=\dfrac{\frac{11}{7}-\frac{4}{7}}{\frac{2}{3}-\frac{2}{3}}=\dfrac{\frac{7}{7}}{0}\ !!!!$

Answer: slope is undefined.

It's a vertical line: $x=\dfrac{2}{3}$