Year 7: Simplification and Expansion of Algebraic Expressions

Quick Reference

  • Like Terms: Terms with the same variable and power
  • Simplify: Combine like terms to make the expression shorter
  • Expand: Remove brackets by multiplying

Collecting Like Terms (Simplifying)

Like terms are terms that have the same variable and power. You can combine them by adding or subtracting.

Examples:

  • 2x + 3x = 5x (both have x, so combine the numbers)
  • 5y + 2y - y = 6y (all have y)
  • 3a + 2b + a = 4a + 2b (a terms combine, b stays separate)

Removing Brackets (Expanding)

When you multiply a bracket by a number or variable, distribute that number/variable to every term inside the bracket.

Rule: a(b + c) = ab + ac

Examples:

  • 2(x + 3) = 2x + 6 (multiply 2 by each term)
  • 3(2y - 1) = 6y - 3 (multiply 3 by each term)
  • -2(a + 4) = -2a - 8 (negative multiplies to all terms)

Steps for Simplification

  1. Identify like terms (same variable and power)
  2. Add or subtract the coefficients
  3. Keep the variable and power the same
Common Mistakes:
  • Trying to combine different variables: 3x + 2y cannot be simplified further
  • Forgetting to multiply all terms in brackets: 2(x + 3) = 2x + 6, not 2x + 3
  • Not distributing negative signs: -2(x - 1) = -2x + 2 (the minus stays)