Absolute Value and Inequality Practice Problems with Solutions

Master absolute value equations and inequalities with step-by-step practice problems. Learn geometric and algebraic methods to solve complex inequality problems.

πŸ“šPractice Absolute Value and Inequality Problems
  • Solve absolute value equations like |x+3| = 7 using algebraic methods
  • Determine distance from zero for positive and negative numbers
  • Apply inequality rules when multiplying or dividing by negative numbers
  • Use geometric methods to solve inequalities like |x-2| < 6
  • Handle two-case scenarios when expressions inside absolute values change sign
  • Master compound inequalities with absolute value expressions

Understanding Absolute Value and Inequality

Complete explanation with examples

An absolute value is the distance from the zero point,
that is, it does not refer to the sum of the number (whether negative or positive),
but it focuses on how far it is from the point 0 0 .

The absolute value is symbolized as follows : β”‚β”‚ β”‚β”‚

Generally we can write:
β”‚βˆ’Xβ”‚=β”‚Xβ”‚=Xβ”‚-Xβ”‚= β”‚Xβ”‚= X

Detailed explanation

Practice Absolute Value and Inequality

Test your knowledge with 23 quizzes

Given:

\( \left|5x + 3\right| \leq 7 \)

Which of the following statements is necessarily true?

Examples with solutions for Absolute Value and Inequality

Step-by-step solutions included
Exercise #1

βˆ’βˆ£x∣=15 -\left|x\right|=15

Step-by-Step Solution

Let's solve the equation βˆ’βˆ£x∣=15 -\left|x\right|=15 . Since the expression inside the absolute value can be either positive or negative, we consider two scenarios:

1. βˆ’x=15 -x = 15 : This implies x=βˆ’15 x = -15 .

2. βˆ’(βˆ’x)=15 -(-x) = 15 : This simplifies to x=15 x = 15 .

Thus, the solutions are x=βˆ’15 x = -15 and x=15 x = 15 .

Answer:

x=βˆ’15 x=-15 , x=15 x=15

Exercise #2

βˆ’βˆ£x∣=8 -\left|x\right|=8

Step-by-Step Solution

Let's solve the equation βˆ’βˆ£x∣=8 -\left|x\right|=8 . The expression inside the absolute value can take two forms:

1. βˆ’x=8 -x = 8 : This gives x=βˆ’8 x = -8 .

2. βˆ’(βˆ’x)=8 -(-x) = 8 : This simplifies to x=8 x = 8 .

Therefore, the solutions are x=βˆ’8 x = -8 and x=8 x = 8 .

Answer:

x=βˆ’8 x=-8 , x=8 x=8

Exercise #3

Given:

∣2xβˆ’1∣>βˆ’10 \left|2x-1\right|>-10

Which of the following statements is necessarily true?

Step-by-Step Solution

Let's solve the problem:
Step 1: Recognize that the inequality we are dealing with is ∣2xβˆ’1∣>βˆ’10 \left|2x-1\right| > -10 .
Step 2: Consider the nature of absolute values: for any real xx, ∣2xβˆ’1∣\left|2x-1\right| is always non-negative (i.e., β‰₯0\geq 0).
Step 3: Observe that the right side of the inequality, βˆ’10-10, is negative. Therefore, the inequality ∣2xβˆ’1∣>βˆ’10\left|2x-1\right| > -10 is always true because ∣2xβˆ’1∣\left|2x-1\right| as a non-negative quantity will always be greater than any negative number.
Step 4: Since the inequality condition always holds true, this means that the statement is valid for all xx.

Therefore, the correct answer is that the inequality holds for all xx.

The solution to the problem is For all x.

Answer:

For all x

Video Solution
Exercise #4

Given:

∣xβˆ’5∣>βˆ’11 \left|x-5\right|>-11

Which of the following statements is necessarily true?

Step-by-Step Solution

The absolute value expression ∣xβˆ’5∣>βˆ’11 \left| x - 5 \right| > -11 inherently suggests that for any real number x x , the inequality holds.

Since the absolute value of any expression is always non-negative and βˆ’11-11 is negative, the condition ∣xβˆ’5∣>βˆ’11 \left| x - 5 \right| > -11 is always satisfied regardless of the choice of x x .

Thus, there is no specific limitation or exceptional circumstance that confines x x to any particular subset of the real numbers.

This implies that no particular statement about x x being greater, less, or constrained to a specific domain can be justified. Therefore, the notion of any statement being "necessarily true" in the conventional sense of constraining x x does not apply.

The correct answer, therefore, is: all x x .

Answer:

all x x

Video Solution
Exercise #5

∣x∣=3 \left|x\right|=3

Step-by-Step Solution

The equation is ∣x∣=3 \left|x\right|=3 , which implies that x x can be 3 or -3. Hence, the solutions are x=3 x=3 and x=βˆ’3 x=-3 .

Answer:

Answers a + c

Frequently Asked Questions

What is the absolute value of a negative number?

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The absolute value of a negative number is always positive. For example, |-5| = 5 because absolute value represents the distance from zero, which is always positive. The distance from -5 to 0 is 5 units.

How do you solve absolute value equations with two solutions?

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When solving |x| = a, there are two cases: x = a and x = -a. For example, |x+3| = 7 gives us x+3 = 7 (so x = 4) and x+3 = -7 (so x = -10). Both solutions should be verified in the original equation.

When do you flip the inequality sign when solving inequalities?

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You flip the inequality sign when multiplying or dividing both sides by a negative number. For example, if -3x < 6, dividing by -3 gives x > -2. This rule ensures the inequality relationship remains mathematically correct.

What is the geometric method for solving absolute value inequalities?

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The geometric method uses the number line to visualize distance. For |x-a| < b, find points exactly distance b from a, then identify all points between them. For |x-a| > b, the solution includes points outside this range.

How do you solve compound absolute value inequalities algebraically?

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Split into two cases based on whether the expression inside is positive or negative. Solve each case separately, then combine the solutions. This method requires checking which values satisfy the original inequality conditions.

What does |x-2| < 6 mean in practical terms?

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This means finding all numbers x whose distance from 2 is less than 6 units. On the number line, these are all numbers between -4 and 8, written as -4 < x < 8.

Why does |x| = -3 have no solution?

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Absolute value always produces non-negative results because it represents distance. Since distance cannot be negative, equations like |x| = -3 have no real solutions.

What are common mistakes when solving absolute value inequalities?

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Common errors include: 1) Forgetting to consider both positive and negative cases, 2) Not flipping inequality signs when dividing by negatives, 3) Incorrectly combining solution sets, and 4) Missing the geometric interpretation of distance.

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