Author note — to cover

Cover why 3x² squares first then multiplies by 3, so x = 4 gives 48 not 144, contrasting (3x)²; include cubes and mixed expressions like 2x² + x, and simple fractional inputs. Out of scope: index laws (simplifying group) and negative inputs (sibling page). Both tiers. (A2)

Introduction

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Practice and continue

Practice

Substituting into terms with powers

Why 3x² means square first then multiply by 3, so x = 4 gives 48 not 144.

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Substituting into a formula

Using formulae such as v = u + at by substituting every known value.