## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

The slope of the line that passes throught two points $(x_1, y_1)$ and $(x_2, y_2)$ can be found using the formula: $m=\dfrac{y_2-y_1}{x_2-x_1}$ Thus, the slope of the line passing through the two given points is: $m=\dfrac{-2-2}{-1-(-1)}=\dfrac{-4}{0} \text{ (undefiend)}$, therefore the line is vertical. To graph, plot both points then connect them using a straight line. Refer to the graph above.