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
- Identify like terms (same variable and power)
- Add or subtract the coefficients
- 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)