A line with a slope of 0 is a horizontal line. The general form of a line in slope-intercept form is:
\[ y = mx + b \]
where \( m \) is the slope and \( b \) is the y-intercept. Since the slope \( m = 0 \), the equation simplifies to:
\[ y = b \]
Since the line passes through the point \( (12, -20) \), we can find \( b \) by noting that the y-value at any point on this line is -20. Therefore, the equation of the line is:
\[ y = -20 \]
This is already in slope-intercept form, where:
- Slope \( m = 0 \)
- Y-intercept \( b = -20 \)
Thus, the final equation of the line is:
\[ y = -20 \]