# How do you find the slope & y-intercept of the equation x = –9?

Apr 14, 2018

The slope is undefined.
There is no $y -$intercept.

#### Explanation:

The equation of a straight line in slope ($m$) and $y -$intercept ($c$) form is : $y = m x + c$

In this case: $x = - 9$ is a vertical straight line through the point $\left(- 9 , 0\right)$ parallel to the $y -$axis.

By definition, the slope of a vertical line is undefined. Also, since it will never intersect the $y -$axis there is no $y -$intercept.

We can see this from the graph of $x = - 9$ below.

graph{0.0001y + x=-9 [-16.02, 16.02, -8.02, 8]}