Exercise 7 Page 384

Let's first highlight the line $\overleftrightarrow{WQ}.$

In the diagram, we can see that the line is also named $g,$ this can be our first alternative name. For the second name, we can use the fact that, when naming a line using two points, the order of the points in the name does not matter. Thus $\overleftrightarrow{QW}$ is also a valid name for the line.