1. Fundamental Concepts
- Definition: Multi-step inequalities involve solving inequalities that require more than one step to isolate the variable.
- Operations: Include addition, subtraction, multiplication, and division of both sides by positive or negative numbers.
- Sign Reversal: Multiplying or dividing both sides of an inequality by a negative number reverses the inequality sign.
2. Key Concepts
Basic Rule:
Distributive Property:
Application: Used in real-world scenarios such as budgeting, physics, and engineering problems.
3. Examples
Example 1 (Basic)
Problem: Solve
Step-by-Step Solution:
- Subtract 4 from both sides:
- Divide both sides by 3:
Validation: Substitute x=3 → Original: 3(3) + 4 = 13 > 10 ✓
Example 2 (Intermediate)
Problem: Solve
Step-by-Step Solution:
- Distribute the 2:
- Simplify:
- Add 2 to both sides:
- Divide both sides by 2:
Validation: Substitute x=3 → Original: 2(3 - 3) + 4 = 4 < 6 ✓
4. Problem-Solving Techniques
- Isolation Strategy: Always start by isolating the variable on one side of the inequality.
- Sign Awareness: Be cautious when multiplying or dividing by negative numbers, as it changes the direction of the inequality.
- Verification Step: After solving, substitute a value from the solution set back into the original inequality to verify correctness.