Learn and revise how to solve quadratic equations by factorising, completing the square and using the quadratic formula with GCSE Bitesize AQA Maths.

The first equation is true when x = 1, the second when x = −1. So 1 and −1 are the two “second roots of unity,” which might be more familiar to you as the two square roots of 1. For any n you can find ...

The two solutions, 2 and –3, are known as the roots of the equation. ... with i representing the square root of –1. Such numbers can be plotted as points on a graph.