# How do you find the slope of the line containing the points (3,-6)and (3,-9)?

Apr 4, 2015
• The X-coordinates of the two points are the same.
It means that the line will be Parallel to the Y Axis. A line parallel to the Y axis (a vertical line) has NO SLOPE . It's undefined .

If we have to provide an explanation with numbers, here is how it would look:

• $S l o p e$ = $R i s e$/$R u n$
The $R i s e$ is the Difference of the Y coordinates of any two points on the line
And the $R u n$ is the Difference of the X coordinates of those two points

• If the coordinates of the points are $\left({x}_{1} , {y}_{1}\right) \mathmr{and} \left({x}_{2} , {y}_{2}\right)$, then $S l o p e = \frac{{y}_{2} - {y}_{1}}{{x}_{2} - {x}_{1}}$
Here, the coordinates are $\left(3 , - 6\right)$ and $\left(3 , - 9\right)$

$S l o p e = \frac{- 9 - \left(- 6\right)}{3 - 3}$
As the denominator will equal Zero, we can say that the Slope of the Line is Undefined .