Chapter 4: Problem 87
Solve. $$|x+6| \geq 7$$
Short Answer
Expert verified
x \geq 1 \ or \ x \leq -13
Step by step solution
01
Understand the Absolute Value Inequality
An absolute value inequality of the form \( |x + a| \geq b \) can be broken down into two inequalities: \( x + a \geq b \) or \( x + a \leq -b \).
02
Set Up the First Inequality
Start with the inequality \( x + 6 \geq 7 \). Solve for \( x \). To do this, subtract 6 from both sides: \( x + 6 - 6 \geq 7 - 6 \). Simplifying this, we get \( x \geq 1 \).
03
Set Up the Second Inequality
Start with the inequality \( x + 6 \leq -7 \). Solve for \( x \). To do this, subtract 6 from both sides: \( x + 6 - 6 \leq -7 - 6 \). Simplifying this, we get \( x \leq -13 \).
04
Combine the Solutions
Combine the results from both inequalities: \( x \geq 1 \) or \( x \leq -13 \). This represents the solution to the original absolute value inequality.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
absolute value
The absolute value of a number is its distance from zero on the number line, regardless of direction. For any real number, the absolute value is always non-negative. Mathematically, we express the absolute value of a number x as \( |x| \). For instance:
- \(|5| = 5\)
- \(|-5| = 5\)
inequality
An inequality is a mathematical statement that indicates one quantity is larger or smaller than another. Unlike equations, inequalities do not assert equality. Common inequality symbols include:
- \( > \): greater than
- \( < \): less than
- \( \geq \): greater than or equal to
- \( \leq \): less than or equal to
solving inequalities
Solving inequalities is somewhat similar to solving equations. However, there is a critical rule: when you multiply or divide both sides of an inequality by a negative number, you must reverse the inequality sign. Let's break down the process with the inequality \( x + 6 \geq 7 \):
- Subtract 6 from both sides: \(x + 6 - 6 \geq 7 - 6 \)
- Simplify the inequality: \( x \geq 1 \)
compound inequalities
Absolute value inequalities often lead to compound inequalities, which are two or more inequalities joined by 'and' or 'or'. The inequality \(|x+6| \geq 7\) breaks into two separate inequalities:
- \( x + 6 \geq 7 \)
- \( x + 6 \leq -7 \)
- For \( x + 6 \geq 7\), subtract 6: \( x \geq 1 \)
- For \( x + 6 \leq -7\), subtract 6: \( x \leq -13 \)