Author note — to cover

Why x squared = k has two solutions while the root sign denotes only the positive one; plus-or-minus notation; giving both roots of 49. Solving quadratic equations lives in Algebra; roots of negatives have no real value at GCSE, and complex numbers are A level. Both tiers. (N6)

Introduction

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Practice and continue

Practice

Positive and negative square roots

Why a squared equation has two solutions while the root sign gives one.

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Cube roots and higher roots

Cube roots and nth roots as the inverse of a power, including negatives.