Question

1. which of the following is a vertical line?

○ $y = x + 7$
○ $y = 7x$
○ $y = 7$
○ $x = 7$

Explanation:

Step1: Recall vertical line form

A vertical line has the form $x = c$, where $c$ is a constant.

Step2: Analyze each option

• $y=x+7$: Slope-intercept form ($y=mx+b$), slanted line.
• $y=7x$: Slope-intercept form, slanted line.
• $y=7$: Horizontal line (constant $y$-value).
• $x=7$: Matches vertical line form $x=c$.

Answer:

D. $x=7$