## Introductory Algebra for College Students (7th Edition)

To find the slope of the line, we use the following formula: $$m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}$$ We use the given values to plug into this formula: $$m = \frac{3 - (-1)}{6 - 6}$$ Simplify: $$m = \frac{4}{0}$$ The slope is undefined, which means that the line is vertical.