Big Ideas Math Algebra 1, 2015
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Big Ideas Math Algebra 1, 2015 View details
7. Graphing Absolute Value Functions
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Exercise 35 Page 161

Be sure to think about the horizontal transformations before any vertical transformations. Work from the inside to the outside. Then make a table of values to find points on the graph.

Transformations:
A horizontal translation 3 units to the right.
A reflection in the x-axis.
A vertical translation 5 units up.
Graph:

Practice makes perfect

First we will go through all the transformations from the graph of f(x)=|x| to the graph of given function. After that we will make a table of values to graph this function.

Transformations

The given equation is a transformation of the parent function f(x)=|x|. We can define each transformation from the inside to the outside. We will start with the transformation closest to x and end with the farthest from x. Let's review our function. d(x)=-|x-3|+5 First, there is a horizontal translation 3 units to the right, |x|⇒|x-3|. Remember, typically |x-h| is a horizontal translation h units to the right, while |x+h| is translated h units to the left.

Next, we have a reflection in the x-axis, |x-3|⇒ -|x-3|.

Finally, we have a vertical translation 5 units up, -|x-3|⇒-|x-3|+5.

Graphing d(x)

To graph the function without going through the entire process of transforming the parent function, we could instead make a table of values. Then we only need to plot the ordered pairs that we find.

x -|x-3|+5 Simplify d(x)
-1 -| -1-3|+5 -|-4|+5 1
1 -| 1-3|+5 -|-2|+5 3
3 -| 3-3|+5 -|0|+5 5
5 -| 5-3|+5 -|2|+5 3
7 -| 7-3|+5 -|4|+5 1

Now we can plot these points and connect them to create our graph of d(x).