To find the slope of the line from the graph, we use the formula for the slope of a line between two points, which is:

$\text{slope} = \frac{\text{change in y}}{\text{change in x}} = \frac{y_2 - y_1}{x_2 - x_1}$

By inspecting the graph, we can choose two points that the red line passes through clearly. Two points that stand out are $(-10, -10)$ and $(10, 10)$.

Now, applying these points to the slope formula:

$\text{slope} = \frac{10 - (-10)}{10 - (-10)} = \frac{20}{20} = 1$

So, the slope of the line is $\boxed{1}$.

Would you like more details on how the slope is calculated?

Here are 5 related questions you might find interesting:

1. How do you find the slope of a vertical line?
2. What is the slope of a horizontal line?
3. Can two different lines have the same slope?
4. How does slope relate to the steepness of a line?
5. How do you find the slope when given an equation in slope-intercept form?

Tip: For a quick slope check, pick two easy-to-read points on the line!