To start, first make sure you can square a bracket in your head

• Now we show you how to complete the square for a very basic example
• Next we put a number more than 1 in front of the x squared term

So hopefully you are feeling confident now, that's good

• Next we do completing the square with a negative x squared term
  • Example 1 (with a -x² term) and Example 2 (with a -2x² term)

Ok so you can complete the square for any quadratic function, so what ....?

Completing the square is useful when you want to solve a quadratic equation that does not factorise easily.

• Here's how we do it

It is also useful for sketching graphs of quadratic functions and locating the minimum or maximum values and the equation of the line of symmetry.

• Here's how it is done*

 

* to come

 

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