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 18 Page 160

Make a table of values to find points on the graph. Note that the graph of b(x) is a V-shaped graph.

Graph:

Comparison: See solution.

Practice makes perfect

Let's graph b(x) first and then we can compare it to the graph of f(x).

Graphing b(x)

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

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

Now we can plot these ordered pairs on a coordinate plane and connect them to draw the graph of b(x). Note that b(x) is a transformation of the graph of the parent function y=|x|, which is V-shaped. Therefore, b(x) will also be a V-shaped graph.

Now that we have graphed our function, we can move on to comparing it to function f(x).

Comparing the Functions

To compare our graph to the graph of f(x)=|x+3|-2, let's first draw this function. We will start with making a table of values, just like we did with function y(x).

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

Now we can use the obtained ordered pairs to graph the function of f(x).

Now when we have drawn the graph of f(x), we can compare b(x) to it by drawing both graphs on the same coordinate plane.

As we can see, the graph of b(x) is a vertical translation 5 units up of the graph f(x).