Answer:
The slope is undefined and the equation of the line is x = 9 ⇒ C
Step-by-step explanation:
- Parallel lines have the same slopes and different y-intercepts
- The slope of any vertical line is undefined
- The equation of any vertical line is x = a, where a is the x-coordinate of a point that lies on the line
- All x-coordinates of the points lie on a vertical line equal
Let us solve the question
∵ The line is parallel to the y-axis
∵ The y-axis is a vertical line
→ By using the second note above
∴ The slope of the y-axis is undefined
→ By using the first note above
∴ The slope of the line is undefined
→ By using the third note above
∵ The equation of the vertical line is x = a
∵ a is the x-coordinate of a point on the line
∵ The line passes through the point (9, -1)
∴ a = 9
∴ The equation of the line is x = 9
