A horizontal line is a straight line that runs parallel to the x-axis on a coordinate plane. It has a slope of 0 and is always at the same y-coordinate.
To graph a horizontal line, plot points that have the same y-coordinate. Connect the points with a straight line to show that it is horizontal.
1. Graph the equation y = 3.
To graph y = 3, plot points (0, 3), (1, 3), (-1, 3), and so on. Connect these points to form a horizontal line parallel to the x-axis at y = 3.
2. Determine if the line with the equation y = -2x + 4 is horizontal.
The line with the equation y = -2x + 4 is not horizontal because it has a non-zero slope (-2).
Horizontal lines have a slope of 0 and run parallel to the x-axis. Their equations are in the form y = c, where c is a constant. When graphing, all points have the same y-coordinate.