A Horizontal line always has an equation in the form y= a number. This means that all the y coordinates of the points on the line will always be the same value.

For the point (3, 11), the y coordinate is 11. This would make the equation of the line be:

y = 11

If you plot the point on a coordinate plane and draw a horizontal line through it, you will see that all the points on the line you drew have y coordinates of 11.