Horizontal and Vertical Line Graphs

Key Questions

  • 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.

  • 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.

  • 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.

    my screenshot

  • 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.

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