Quadratic equations and completing the square 

My granddaughter was revising for GCSE Maths asked me about “completing the squares” in algebra used for solving quadratic equations and I could not recall the technique. Later after a bit of googling I realised that it was the method used to determine the classic quadratic equation:

Once proved hereafter I used either inspection or this formula to solve quadratic equations and “completing the squares” faded in my memory. 

The document below expands upon this, showing the “completing the squares” technique, a couple of examples and finally derivation of the quadratic equation. You can also download pdf by clicking on button