Some quadratic equations cannot be solved by factorising and so an alternative method is the quadratic formula. It is based on a method called completing the square.

#### Rule to remember:

This tutorial shows you when to use it, clues that are given in a question and common mistakes that are often made.

## How to Derive the Quadratic Formula

ToheedOctober 9, 2016 at 10:31 amThank you so much for your videos

one thing i think you should do is put harder examples in videos as sometimes the exam questions look harder to the examples.

SunflowerBaeDecember 22, 2016 at 7:37 amHelpful tutorials.

Is this for core or extended?