Answer
The slope is undefined.
Work Step by Step
To find the slope, we use the formula $m=\frac{y_2-y_1}{x_2-x_1}$.
We plug in the $x$ and $y$ values given to us in the coordinate pairs: $m=\frac{6-(-4)}{6-6}$
We simplify above and below the fraction bar with subtraction: $m=\frac{10}{0}$
Any number divided by $0$ is undefined. Therefore, the slope of this line is undefined.
