Sectieoverzicht

  • When to use the quadratic formula

    The quadratic formula can be used to solve any quadratic equation, even those that can be easily factorised. However, solving quadratic equations by factorisation is still the simplest and quickest method. So, use factorisation whenever you can. But, as long as you know the values of \(a\), \(b\) and \(c\) you can use the quadratic formula.

    Before, you learn about the quadratic formula you should understand how to complete the square. The quadratic formula is easily derived from a quadratic equation is standard form by completing the square. The video explains the steps of completing the square using a visual perspective. 

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      Deriving the quadratic formula

      The quadratic formula can be easily derived by using the method of completing the square. This method is explained in the next video. 

      If you'd like to refer to a text-based proof you can find that here: Quadratic Formula proof review.
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      Practise using the quadratic formula

      To practise using the quadratic formula, try this next activity: Quadratic formula.