What is the slope and y-intercept of the line #x=-6#?

1 Answer
Jun 12, 2016

The line is vertical.
It does not have a y-intercept at all.
The gradient is undefined (infinite).
This vertical line does not cross the #y-# axis anywhere.


#x = -6# is a vertical line crossing the x-axis at -6.
It does not cross the y-axis at all, so there is no y-intercept.

Lines which are vertical are said to have an infinite or undefined gradient.
The definition of gradient is #("change in y-values")/("change in x-values")#

As there is no change in the x-values the denominator would be 0.
Vertical lines are only ones which cannot be written in the standard form of # y = mx + c# and are always given as #x = .....#