The distance from 0 is no more than 5, so the solution stays between the two endpoints.
Solving Absolute-Value Inequalities
Translate an absolute-value inequality into an AND or OR compound inequality, solve it carefully, and write the solution with inequalities, a number-line graph, and interval notation.
01 · Watch
Lesson video
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02 · Understand
Learning targets
- Translate absolute-value inequalities into compound inequalities.
- Choose the AND shortcut for inward-pointing inequalities.
- Choose the OR shortcut for outward-pointing inequalities.
- Write solution sets using inequalities, graphs, and interval notation.
03 · Vocabulary
Key definitions
Connect the algebraic shortcut to distance on a number line.
- 01Absolute-value inequality
- An inequality containing an absolute-value expression, such as .
- 02Distance meaning
- is the distance from to 0, so it is never negative.
- 03AND form
- When the inequality points inward, becomes .
- 04OR form
- When the inequality points outward, becomes .
- 05Union
- The symbol joins two separate solution intervals.
04 · Apply
Worked examples
Isolate the absolute-value expression before applying a shortcut.
- Subtract 4 from all three parts: .
- Divide all three parts by 3: .
The distance from 0 is at least 4, so the solution lies on the two outside rays.
- Isolate the absolute value: .
- Use the AND form: .
- Subtract 6: .
- Divide by and reverse both inequalities: .
- Reorder the chain: .
- Divide by and reverse the inequality: .
05 · Avoid
Common mistakes
First isolate the absolute-value expression.
Outward-pointing inequalities create two rays joined by OR.
The second boundary is the negative of the first.
Reverse every inequality symbol affected by the division.
Use an open circle and a parenthesis for or .
Use between the two separate intervals.
06 · Check yourself
Quick check
Choose AND or OR before opening each answer.
1Rewrite without absolute-value bars.
. The inequality points inward, so use AND.
2Rewrite without absolute-value bars.
. The inequality points outward, so use OR.
3Solve .
. Start with .
4Solve .
.
5Write in interval notation.
.
07 · Revisit
Transcript and assigned practice
Search the corrected transcript for an example, then complete the eKadence worksheet Absolute Value Inequalities.
Download corrected transcript