Chapter 2: Problem 32
For Problems \(31-54\), solve each inequality. $$ |x-3|>9 $$
Short Answer
Expert verified
\(x < -6\) or \(x > 12\).
Step by step solution
01
Understanding the Absolute Value Inequality
The expression \(|x-3|>9\) means you want to find all values of \(x\) that make the distance between \(x\) and 3 greater than 9. This means we need to consider two separate cases: \(x-3 > 9\) or \(x-3 < -9\).
02
Case 1: Solving \(x-3>9\)
To solve \(x-3>9\), we add 3 to both sides of the inequality to isolate \(x\). This gives us \(x>12\).
03
Case 2: Solving \(x-3
To solve \(x-3<-9\), we again add 3 to both sides. This time, it yields \(x<-6\).
04
Combining the Solutions
The solution to the inequality \(|x-3|>9\) is the union of the solutions from both cases. Thus, \(x< -6\) or \(x> 12\). In interval notation, this solution is written as \((-∞, -6) \cup (12, ∞)\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Solving Absolute Value Inequalities
When facing an absolute value inequality like \(|x-3|>9\), remember that absolute value represents distance. Here, it means finding numbers whose distance from 3 is greater than 9. To break it down:
- The absolute value inequality \(|x-3|>9\) suggests two scenarios: the number is more than 9 units away to the left or to the right of 3 on a number line.
- We split this inequality into two distinct simpler inequalities to solve: \(x-3 > 9\) and \(x-3 < -9\).
- For the inequality \(x-3>9\), add 3 to both sides to get \(x>12\).
- For \(x-3<-9\), also add 3 to both sides to get \(x<-6\).
Understanding Interval Notation
Interval notation offers a neat way to describe the set of solutions for an inequality. Let's delve deeper:
- After solving the absolute value inequality \(|x-3|>9\), we found two conditions: \(x>12\) and \(x<-6\).
- These conditions mean \(x\) is either less than \(-6\) or greater than \(12\). Neither includes \(-6\) or \(12\) because \(>\) and \(<\) are strict inequalities.
- \((12, ∞)\) represents numbers greater than 12 moving towards infinity, excluding 12 itself.
- \((-∞, -6)\) indicates numbers falling below \(-6\) extending to negative infinity, excluding \(-6\).
Inequality Solutions and Their Interpretation
Solving absolute value inequalities involves not just calculating the numbers but understanding their meaning and interpreting solutions correctly:
- Each solved inequality points to a range of numbers that fulfill the original condition.
- For \(x-3 > 9\), the solution \(x>12\) represents any number larger than 12 satisfying the distance condition from 3.
- Similarly, \(x-3 < -9\) leading to \(x<-6\) describes numbers less than \(-6\) that work.
- The number line approach works wonders here by marking regions like \((-∞, -6)\) and \((12, ∞)\), highlighting the portions of interest.
- Graphs can clearly showcase where \(x\) meets the inequality's criteria, giving a visual affirmation of the solution set.