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

  1. Group by power: (5x2 - 2x2) + (-3x + 4x) + (2 - 7)
  2. 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)

  1. Expand first: 6x + 4 + 4x - 4
  2. 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