The Quadratic Formula

Quadratic Formula

• The solutions of the quadratic equation ax^2 + bx + c = 0 where a not= 0 are given by

  

  • You can use this formula for any quadratic equation
  • But be careful, not all quadratic equations have a solution

Checklist

• Equation is in the form ax^2 + bx + c = 0
• Write down your values of a.b and c before you substitute
• Use brackets when you are substituting negative numbers
• Show what you have substituted in the formula
• Simplify what is under the square root and write this down
• The +- symbol means you need to do two calculations

Working it out

• You are asked to find solutions
• This tells you that you are solving a quadratic equation
• You must give your answer correct to the certain amount
• Write down at least 5 figures after the decimal point on the calculator display before giving your final answer
• You might need to use the S-D button on your calculator to get the answer as a decimal

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