Simplifying Expressions

MathematicsAQAEdexcelGCSEUnit: Algebra
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The basics

What Does "Simplify" Mean?

What Does "Simplify" Mean?

Imagine your pencil case has 3 red pens and 2 blue pens, then someone gives you 4 more red pens and takes 1 blue pen. You wouldn't say "I have 3 red + 2 blue + 4 red − 1 blue" - you'd say "7 red and 1 blue"! Simplifying is just combining things that are the same type. In algebra, "3x + 2y + 4x − y" becomes "7x + y".

Visual Guide

Simplifying expressions - collecting like terms
Spotlight
What Are "Like Terms"?

Like terms have exactly the same variable(s) with the same power(s)

Exam tip

Earn the mark scheme marks

Common Mistakes to Avoid

✗ 3x + 2y = 5xy ✓ 3x + 2y (can't simplify) Unlike terms stay separate
✗ 2x + 3x² = 5x³ ✓ 2x + 3x² (can't simplify) Different powers = unlike terms
✗ 5x − 3x = 2 ✓ 5x − 3x = 2x Keep the variable after combining
✗ −x² + 3x² = 2x² ✓ −x² + 3x² = 2x² This one is correct! Watch signs carefully
✗ Forgetting −x means −1x ✓ 5x − x = 5x − 1x = 4x Invisible coefficient is 1

Now try it yourself

Quiz · Question 1 of 11

Which two terms are like terms?

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