# How do you determine the missing coordinate P(3, 2) and Q(8,_) if slope is -1?

##### 1 Answer
Jun 15, 2015

Q has coordinates (8,-3)

#### Explanation:

The slope between two points, P and Q is defined to be
$m = \frac{{y}_{Q} - {y}_{P}}{{x}_{Q} - {x}_{P}}$

Given $P = \left(3 , 2\right)$, $Q = \left(8 , x\right)$, and $m = - 1$
we have
$\textcolor{w h i t e}{\text{XXXX}}$$- 1 = \frac{x - 2}{8 - 3}$

$\Rightarrow$$\textcolor{w h i t e}{\text{XXXX}}$$x - 2 = - 5$

$\Rightarrow$$\textcolor{w h i t e}{\text{XXXX}}$$x = - 3$