Horizontal and Vertical Line Graphs

Key Questions

What are horizontal or vertical line graphs?

A horizontal has the equation #y=b# with #b# any constant number
A vertical has the equation #x=c# with #c# any constant number

A normal linear equation is mostly of the form #y=mx+b#
where #m# is the slope. In a horizontal graph, the slope is 0.
The #b# (called the #y#-intercept) tells you where the graph crosses the #y#-axis.

For the vertical graph a similar story goes and #c# is called the #x#-intercept.

MeneerNask · 1 · Jan 5 2015
What is the equation for the y-axis?

Answer:

#x=0#

Explanation:

For any point on the Y-axis, #x# is equal to zero;
furthermore, if any point for which the #x#-coordinate is equal to zero will be on the Y-axis.

Alan P. · 1 · Mar 23 2018
What is the equation for the x-axis?

The x-axis is like a number line, isn't it? Every point on the x-axis has a y-coordinate of 0 like this: (-4,0), (3,0), (2.7, 0) and (0,0).

If all of these points have the same y-coordinate, it follows that the equation of that line must be y = 0! It would be the same idea for any horizontal line, since the slope = 0. Calculate the slope between any two of those points:
m = #(0-0)/(3-(-4))# using (-4,0) and (3,0).
You would write the equation now like: y = 0x + 0, or just y = 0.

Think about another horizontal line that goes through the points (8,3), (0,3), (-14, 3), and (4.1, 3). Calculate the slope:

m =#(3-3)/(-14-0)# using the points (0,3) and (-14,3).
The y-intercept is (0,3) and therefore the equation of that line is y = 0x + 3, or just y = 3.

MrsRudolph221 · 8 · Oct 23 2014
What are some examples of when you would see horizontal or vertical line graphs?

An equation of a vertical line can be written in the form

#x=a#,

where #a# is a constant.

An equation of a horizontal line can be written in the form

#y=b#,

where #b# is a constant.

I hope that this was helpful.

Wataru · 1 · Nov 5 2014