1. **State the problem:** Find the gradient (slope) of the line passing through the points $(-3,0)$ and $(0,-6)$.\n\n2. **Formula:** The gradient $m$ of a line through points $(x_1,y_1)$ and $(x_2,y_2)$ is given by:\n$$m = \frac{y_2 - y_1}{x_2 - x_1}$$\n\n3. **Substitute the points:** Here, $(x_1,y_1) = (-3,0)$ and $(x_2,y_2) = (0,-6)$.\n$$m = \frac{-6 - 0}{0 - (-3)} = \frac{-6}{3}$$\n\n4. **Simplify:**\n$$m = -2$$\n\n5. **Interpretation:** The gradient of the line is $-2$, meaning the line falls 2 units vertically for every 1 unit it moves horizontally to the right.