Math Problem Statement

Determine all numbers A > 0 for which the following statements hold: 1. If |x - 2| < 1 then |4x - 8| < A. 2. If |x + 5| < 4 then |-3x - 15| < A.

Solution

We are tasked with determining all positive numbers AA for which two conditions hold.

Step-by-step Solution:

1. Analyze the first condition:

If x2<1 then 4x8<A\text{If } |x - 2| < 1 \text{ then } |4x - 8| < A

First, simplify 4x8|4x - 8|: 4x8=4x2|4x - 8| = 4|x - 2| Therefore, the condition becomes: x2<1    4x2<A|x - 2| < 1 \implies 4|x - 2| < A Since x2<1|x - 2| < 1, multiplying both sides by 4 gives: 4x2<44|x - 2| < 4 Thus, we need A>4A > 4 for the first inequality to hold.

2. Analyze the second condition:

If x+5<4 then 3x15<A\text{If } |x + 5| < 4 \text{ then } |-3x - 15| < A

Simplify 3x15|-3x - 15|: 3x15=3x+5|-3x - 15| = 3|x + 5| Therefore, the condition becomes: x+5<4    3x+5<A|x + 5| < 4 \implies 3|x + 5| < A Since x+5<4|x + 5| < 4, multiplying both sides by 3 gives: 3x+5<123|x + 5| < 12 Thus, we need A>12A > 12 for the second inequality to hold.

Conclusion:

For both inequalities to hold, AA must be greater than 12. Therefore: A>12A > 12

Would you like a deeper explanation on any step or have any questions? Here are some related questions to think about:

  1. What is the geometric interpretation of absolute value inequalities?
  2. How does multiplying an absolute value inequality by a constant affect the solution?
  3. How would the solution change if we had a different range for xx?
  4. What happens if we introduce additional constraints on AA?
  5. Can we generalize this method to other similar inequalities?

Tip: When dealing with absolute value inequalities, always consider breaking the inequality into two cases or simplifying using properties like ax+b=ax+b/a|ax + b| = a|x + b/a|.

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Math Problem Analysis

Mathematical Concepts

Absolute Value Inequalities
Linear Transformations
Algebraic Simplification

Formulas

|ax + b| = a|x + b/a|
Inequality properties for absolute values
Linear expression simplification

Theorems

Properties of absolute values
Multiplying inequalities by positive constants

Suitable Grade Level

Grades 9-11