Answer
The line $x = 5$ is a vertical line. All vertical lines have undefined slopes. All points on this line have different $y$ values but the same $x$ value. This line would contain the point $(5, 0)$, which is the x-intercept.
Work Step by Step
The line $x = 5$ is a vertical line. All vertical lines have undefined slopes. All points on this line have different $y$ values but the same $x$ value. This line would contain the point $(5, 0)$, which is the x-intercept.