4.7  Graphs of Absolute Value Equations

Mrs. Agriesti's Algebra

Goal:  To graph absolute value equations.

The graph of an absolute value equation is not a straight line, it forms a V

To graph an absolute value equation:

  1. Solve for y.
  2. Find  the vertex:  (a) The x-coordinate of the vertex is the number that makes the absolute value part of the equation equal zero.  (b) The y-coordinate of the vertex is the constant that is being added to or subtracted from the absolute value part.
  3. Make a table of values.  Use the x-coordinate of the vertex as your middle x-value. 
  4. Plot the points from your table.
 

Sketch the Graph:

There is no need to solve for y (it is already by itself).

The absolute value part of the equation is |x - 3|.  Positive 3 would make it equal to 0.  So the x-coordinate of the vertex is 3.  The y-coordinate of the vertex is 5.

Make a table with x = 3 in the middle.  Fill it in. 
Show all work.

Notice that I used multiples of 3 for my other x-values,  I did that because of the fraction 2/3.

Now plot the points, use a
straight-edge to connect them, and label the graph.

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