Chapter 7 - Algebra: Graphs, Functions, and Linear Systems - 7.2 Linear Functions and Their Graphs - Concept and Vocabulary Check - Page 460: 8

vertical

RECALL: The graph of a line whose equation is of the form $x=h$ is a vertical line whose x-intercept is $h$. The given line $x=-2$ has $h=-2$. Thus, its graph is a vertical line whose x-intercept is $-2$. Therefore, the missing expression in the given statement is: vertical