Chapter 1: Problem 36
For what value(s) of \(x\) is \(|x|=4\) true?
Short Answer
Expert verified
The values of \( x \) are \( 4 \) and \( -4 \).
Step by step solution
01
Understand the Absolute Value Function
The absolute value of a number is its distance from zero on the number line, without regard to direction. Therefore, \(|x| = 4\) means that the distance of \(|x|\) from zero is 4.
02
Set Up Two Equations
Given \(|x| = 4\), the number \ (x) \ can be either positive or negative. This gives us two equations: \( x = 4 \) and \( x = -4 \).
03
Solve Each Equation
Solving the first equation: \( x = 4 \). Solving the second equation: \( x = -4 \).
04
Verify the Solutions
Check both solutions by substituting back into the absolute value equation. \( |4| = 4 \) and \( |-4| = 4 \), both are true.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
absolute value function
The absolute value function is a fundamental mathematical concept that measures the distance of a number from zero on a number line. It is always a non-negative number. For any real number \( x \), the absolute value is denoted as \( |x| \).
Here are a few key points:
For example, \( |4| = 4 \) and \( |-4| = 4 \), because both 4 and -4 are 4 units away from zero.
Here are a few key points:
- If \( x \) is positive, \( |x| = x \).
- If \( x \) is negative, \( |x| = -x \).
- If \( x = 0 \), \( |x| = 0 \).
For example, \( |4| = 4 \) and \( |-4| = 4 \), because both 4 and -4 are 4 units away from zero.
distance from zero
Another way to understand the absolute value function is to think of it as the distance a number is from zero on a number line. Since distance is always non-negative, the absolute value is always positive or zero.
Consider \( |x| = 4 \):
Consider \( |x| = 4 \):
- This means the number \( x \) is exactly 4 units away from zero.
- There are only two numbers on a number line that satisfy this condition: 4 and -4.
solving equations
Solving absolute value equations involves understanding the definition of absolute value and its properties. Here's how to solve \( |x| = 4 \):
- Recognize that the absolute value equation \( |x| = 4 \) can be split into two separate linear equations because the distance of \( x \) from zero can be either 4 or -4.
- Set up the two possible equations: \( x = 4 \) and \( x = -4 \).
- Solve each equation separately:
- From \( x = 4 \), we get \( x = 4 \).
- From \( x = -4 \), we get \( x = -4 \).
positive and negative solutions
Absolute value equations often yield both positive and negative solutions because distance is independent of direction. For the equation \( |x| = 4 \):
It's essential to verify both solutions by substituting back into the original equation:
- The positive solution is \( x = 4 \) because the distance from zero to 4 is 4 units.
- The negative solution is \( x = -4 \) because the distance from zero to -4 is also 4 units.
It's essential to verify both solutions by substituting back into the original equation:
- For \( x = 4 \), \( |4| = 4 \), which satisfies the equation.
- For \( x = -4 \), \( |-4| = 4 \), which also satisfies the equation.