Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
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Exercise 7 Page 20

Describe the parent function and then use a table of values to graph the functions.

Graph:

Transformations:
A reflection in the x-axis.
A horizontal translation 2 units left.
A vertical translation 7 units down.

Practice makes perfect

The given function is an absolute value function, so its parent function is y=|x|. We will start by graphing both functions in one coordinate plan. Then we will compare them to describe the transformation.

Graphing the Functions

To graph both of the functions, we will use the table of values. We will choose a variety of x-values: at least one negative, 0, and at least one positive.

x y=|x| f(x)=-|x+2|-7
-3 |-3|= 3 -|-3+2|-7= -8
-2 |-2|= 2 -|-2+2|-7= -7
0 |0|= 0 -|0+2|-7= -7
1 |1|= 1 -|1+2|-7= -10

Now let's plot the functions using these points! Remember that the graph of absolute value functions is V-shaped.

Comparing the Functions

Having drawn our functions, we can describe the transformation.
We see that each y-value is being moved to its opposite value (the graph is flipped over the x-axis), then is shifted 1 unit to the left and 7 units down. These are: a reflection in the x-axis, a horizontal translation and a vertical translation.