Solving Quadratic Equations (AQA AS Maths): Revision Note

Solving quadratic equations

Solving quadratic equations

• We can solve quadratic equations when they are written in the form 

• If given an unusual looking equation, try to rearrange it into this form first

• The three ways to solve a quadratic you must know are

  • Factorising

  • Completing the square

  • Quadratic formula

How do I solve by factorisation?

• Factorising is a great way to solve a quadratic quickly but won't work for all quadratics

• If the numbers are simple, try factorising first

• Once factorised, set each bracket to = 0 and solve

How do I solve by completing the square?

• Completing the square will work for any quadratic

• Make sure you know how to complete the square

• Remember this will help with questions involving turning points too

  

   

How do I solve using the quadratic formula?

• The quadratic formula might look complicated but it just uses the coefficients a, b and c from the quadratic equation 

• The quadratic formula will work for any quadratic

How do I solve using a calculator?

• Most calculators now have the ability to solve quadratics

• Get used to how your calculator functions work

  

• So the solution to the quadratic equation  are x = 1.5 and x = -4