#### Get the first move right and the rest follows

## Martin Hansen

###

To solve the following equation :

###

First multiply through by 4a :

###

Complete the square within the square brackets :

###

###

Square-root both sides :

###

And the well-known formula is there for the taking.

#### M500 : The Open University's mathematics magazine.

September 2008

#### Staff INSET presentation at Shrewsbury School.

November 2009

#### All images, text and file downloads © 2004 - 2012, The MathMagical Software Company.

###