To calculate the slope of a line, you use the slope formula:

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

Here’s what the formula means:

1. Choose two points on the line, $(x_1, y_1)$ and $(x_2, y_2)$.
2. Subtract the $y$-coordinates ($y_2 - y_1$) to find the change in $y$ (vertical change).
3. Subtract the $x$-coordinates ($x_2 - x_1$) to find the change in $x$ (horizontal change).
4. Divide the change in $y$ by the change in $x$.

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Example:

If you have two points $(1, 2)$ and $(4, 8)$, calculate the slope as follows:

1. Identify coordinates: $(x_1, y_1) = (1, 2)$ and $(x_2, y_2) = (4, 8)$.
2. Find the change in $y$: $y_2 - y_1 = 8 - 2 = 6$.
3. Find the change in $x$: $x_2 - x_1 = 4 - 1 = 3$.
4. Calculate the slope: $m = \frac{y_2 - y_1}{x_2 - x_1} = \frac{6}{3} = 2$

Thus, the slope is $m = 2$.

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Let me know if you'd like me to expand or clarify anything!

Here are 5 related questions you might find interesting:

1. How do you determine the slope from a graph?
2. What is the slope of a horizontal or vertical line?
3. How do you interpret the slope in real-world applications (e.g., speed)?
4. What does a positive or negative slope indicate about the line?
5. How do you calculate the slope of a curve at a point (instantaneous slope)?

Tip: The slope measures the "steepness" of a line and tells you how much $y$ changes for a unit change in $x$.