To solve junior-level absolute value problems, you need to understand the basic concept of absolute value: the distance of a number from zero on a number line, regardless of direction. Here's a step-by-step guide to solving these problems:

Step-by-Step Guide

1. Understand the Definition of Absolute Value

The absolute value of a number is always positive or zero. For example:

• $|5| = 5$
• $|-5| = 5$
• $|0| = 0$

2. Set Up the Equation

An absolute value equation looks like: $|x| = a$ Where $a$ is a non-negative number. The equation means that $x$ can be $a$ or $-a$, since both values have the same absolute value.

3. Solve Simple Absolute Value Equations

If you have $|x| = a$, break it down into two cases:

• $x = a$
• $x = -a$

Example 1: Solve $|x| = 4$

• $x = 4$ or $x = -4$

4. Solve Absolute Value Equations with Expressions

When dealing with equations like $|x + 3| = 7$, follow these steps:

Example 2: Solve $|x + 3| = 7$

• Break it into two cases:
  1. $x + 3 = 7$
  2. $x + 3 = -7$
• Solve each equation:
  1. $x = 7 - 3 = 4$
  2. $x = -7 - 3 = -10$
• Solution: $x = 4$ or $x = -10$

5. Check for Extraneous Solutions (Optional but Important)

In some cases, particularly for more complex problems, solving absolute value equations may give solutions that don't satisfy the original equation. Always check your answers by substituting them back into the equation to make sure they are valid.

6. Solve Absolute Value Inequalities

For inequalities, you break them into two cases but pay attention to the direction of the inequality.

Example 3: Solve $|x| < 5$

• This means:
  • $x < 5$ and $x > -5$
• So the solution is: $-5 < x < 5$

7. Combine Solutions if Needed

For complex problems that involve multiple absolute value terms, you may need to combine the solutions of different cases.

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Relative Questions:

1. How do you solve absolute value inequalities with "greater than" instead of "less than"?
2. How can you apply the absolute value concept to solve real-world distance problems?
3. What changes when you solve absolute value equations involving quadratic expressions?
4. How do you solve an equation like $|x| = |y|$?
5. What is the graphical interpretation of absolute value equations?

Tip:

Always remember that an absolute value equation like $|x| = -a$ has no solution because absolute value cannot equal a negative number.