Chapter 8 - Polar Coordinates; Vectors - Section 8.2 Polar Equations and Graphs - 8.2 Assess Your Understanding - Page 606: 19

$x=-2$ a vertical line 2 units left of the pole. See graph.

1. Use the formula $r\ cos\theta=x$, we have $r\ cos\theta=-2\rightarrow x=-2$ 2. We can identify the above equation as a vertical line 2 units left of the pole. 3. See graph.