The slope $m$ of a line passing through two points $(x_1, y_1)$ and $(x_2, y_2)$ is calculated using the formula:

$m = \frac{y_2 - y_1}{x_2 - x_1}$

Here, the given points are $(9, 0)$ and $(3, -2)$. Substituting these values:

$m = \frac{-2 - 0}{3 - 9}$

$m = \frac{-2}{-6}$

$m = \frac{1}{3}$

Thus, the slope of the line is:

$m = \frac{1}{3}$

Let me know if you want further clarification or additional details.

Here are 5 related questions to consider:

1. What is the equation of the line passing through these two points?
2. How does the slope relate to the angle of inclination of the line?
3. Can you calculate the midpoint of the line segment joining these points?
4. How would the slope change if the points were reversed?
5. What are some real-life applications of calculating slopes?

Tip: Always remember that a negative denominator in the slope calculation can be simplified by multiplying by $-1$ to avoid confusion.