What is the equation of a line perpendicular to the x-axis that passes through the point (-1,8), and what is the slope?

Answer 1

In general equation of a line perpendicular to x - axis is x=a where a is a real number. It also called vertical line.

Since you are looking for a vertical line which passes through point (x, y)=(-1, 8) this line equation is x=-1.

A vertical line has undefined slope