#### Answer

slope $=-2$

#### Work Step by Step

RECALL:
The slope $m$ of the line that passes through the points $(x_1, y_1)$ and $(x_2, y_2)$ is given by the formula
$m=\dfrac{y_2-y_1}{x_2-x_1}$
Use the formula above to solve for the slope and obtain:
$m=\dfrac{12-8}{3-5}=\dfrac{4}{-2}=-2$