On the other hand, the equation of any horizontal lines come in the form
- where is just a constant.
This time around, the equation doesn't have any variable x. The absence of x means that the variable x can take any numerical values while the value of y is being held constant. Here's an example.
Graph the horizontal line .
Since we have no x-variable in the equation, it is okay to pair the y-coordinate of "-2" with any x-values. When you construct the table of values for this, the y-coordinates will be the same throughout while the x-coordinates will assume different unique values.
Observe, the y-column is populated with the same value of -2.
Graphing these points in the xy axis, we have a horizontal line parallel to the x-axis and passing through the point .