Question

Which of the following is parallel to the line of equation x=a?

• A. x-axis
• B. origin
• C. y-axis
• D. none of the above

Answer 1

The correct option is C

y-axis

Slope of x=a is undefined.

Two lines are parallel if their slopes are equal.

Slope of x-axis = 0.
Slope of y-axis = undefined.
There is no such thing as slope for origin as the origin is just a point.

So, the given line x = a is parallel to y-axis.