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 xvariable in the equation, it is okay to pair the ycoordinate of "2" with any xvalues. When you construct the table of values for this, the ycoordinates will be the same throughout while the xcoordinates will assume different unique values.
Observe, the ycolumn is populated with the same value of 2.
Graphing these points in the xy axis, we have a horizontal line parallel to the xaxis and passing through the point .