To write the equation of the horizontal line passing through the point $(3, 8)$:

• A horizontal line has the same $y$-value at every point, meaning the equation of the line is simply $y = \text{constant}$.
• Since the line passes through the point $(3, 8)$, the $y$-coordinate is always 8.

Thus, the equation of the horizontal line is: $y = 8$

Would you like further details or have any questions?

Here are 5 related questions you might find helpful:

1. What is the equation of a vertical line passing through $(3, 8)$?
2. How would you write the equation of a horizontal line passing through $(5, -4)$?
3. What is the general form of the equation for a line with a given slope and point?
4. How do you find the slope of a line given two points?
5. What is the difference between the equations of horizontal and vertical lines?

Tip: Horizontal lines always have equations of the form $y = c$, where $c$ is the constant $y$-value.