How do I decide the best method to solve a quadratic equation?
- A quadratic equation is of the form
- If it is a calculator paper then use your GDC to solve the quadratic
- If it is a non-calculator paper then...
- you can always use the quadratic formula
- you can factorise if it can be factorised with integers
- you can always complete the square
How do I solve a quadratic equation by the quadratic formula?
- If necessary rewrite in the form
- Clearly identify the values of a, b & c
- Substitute the values into the formula
- This is given in the formula booklet
- Simplify the solutions as much as possible
How do I solve a quadratic equation by factorising?
- Factorise to rewrite the quadratic equation in the form
- Set each factor to zero and solve
How do I solve a quadratic equation by completing the square?
- Complete the square to rewrite the quadratic equation in the form
- Get the squared term by itself
- If is negative then there will be no solutions
- If is positive then there will be two values for
- Solve for x
- When using the quadratic formula with awkward values or fractions you may find it easier to deal with the " " (discriminant) first
- This can help avoid numerical and negative errors, improving accuracy
Solve the equations: