Big Ideas Math Algebra 1, 2015
BI
Big Ideas Math Algebra 1, 2015 View details
6. Solving Absolute Value Inequalities
Continue to next subchapter

Exercise 5 Page 91

Create an or compound inequality because the absolute value is greater than the given value.

Solution Set: d<-12 or d>-6
Graph:

Practice makes perfect
We are asked to find and graph the solution set for all possible values of d in the given inequality. |d+9|> 3 To do this, we will create a compound inequality by removing the absolute value. In this case, and since d+9 can be written as d-(- 9), the solution set contains the numbers that make the distance between d and - 9 greater than 3 in the positive direction or in the negative direction. d+9 > 3 or d+9< - 3

Let's isolate d in both of these cases before graphing the solution set.

Case 1

We can solve the inequality by performing inverse operations on both sides of the inequality. Let's solve the first case.
d+9 > 3
d>-6
This inequality tells us that all values greater than - 6 will satisfy the inequality.

Case 2

Now, let's solve the second case of the inequality.
d+9 < - 3
d< -12
This inequality tells us that all values less than - 12 will satisfy the inequality.

Solution Set

The solution to this type of compound inequality is the combination of the solution sets. First Solution Set:& d>-6 Second Solution Set:& d< -12 Combined Solution Set:& d< -12 or d>-6

Graph

The graph of this inequality includes all values less than - 12 or greater than - 6. We show this by using open circles on the endpoints.