# If the slope is negative is the rise OR the run negative?

Jul 6, 2015

Either but not both.

#### Explanation:

If you have two points $\left({x}_{1} , {y}_{1}\right)$ and $\left({x}_{2} , {y}_{2}\right)$ on a line, then the slope $m$ of the line is given by the formula:

$m =$rise$/$run$= \frac{\Delta y}{\Delta x} = \frac{{y}_{2} - {y}_{1}}{{x}_{2} - {x}_{1}}$

Suppose $m < 0$

If the rise is positive, then the run must be negative in order that
rise / run < 0.

If the rise is negative, then the run must be positive in order that
rise / run < 0.