Year 7: Simplification and Expansion of Algebraic Expressions (Advanced)
Quick Reference
- Like Terms: Exact same variables with exact same powers
- Expand: Distribute across all terms, watch signs carefully
- Factor: Reverse of expanding; find common factors
Advanced Simplification Techniques
In advanced expressions, be systematic about grouping like terms.
Example with mixed terms:
5x2 - 3x + 2 - 2x2 + 4x - 7
- Group by power: (5x2 - 2x2) + (-3x + 4x) + (2 - 7)
- Combine: 3x2 + x - 5
Expanding Complex Expressions
With multiple variables and powers, expand methodically:
- 2x(3x + 4y - 5) = 6x2 + 8xy - 10x (multiply 2x by each term)
- -3(2a2 - ab + 1) = -6a2 + 3ab - 3 (distribute negative)
- a(a + b + c) = a2 + ab + ac (variable multiplication)
Combining Expansion and Simplification
Multi-step problems often require both skills:
Example: 2(3x + 2) + 4(x - 1)
- Expand first: 6x + 4 + 4x - 4
- Simplify: 10x
Introduction to Factoring
Factoring is the reverse of expanding. Find the common factor:
- 2x + 4 = 2(x + 2) (common factor is 2)
- 3ab + 6a = 3a(b + 2) (common factor is 3a)
- x2 + 3x = x(x + 3) (common factor is x)
Key Insight: When you multiply out factored forms, you should get back the original expression. Use this to check your work!
Common Mistakes:- Forgetting to change signs when distributing negatives
- Not identifying the greatest common factor when factoring
- Leaving out terms or changing their signs in multi-bracket expansions