SOLVE QUADRATIC EQUATIONS USING THE GENERAL FORMULA

TIP: When doing these sort of problems, remember:

a) If your algebra isn't too strong, then rather than completing the square to solve a     quadratic which can't be factorised, use this equation.

b) At GCSE level you will never end up needing to find the square root of a negative
    number, if this happens in your calculation - check your handling of negative numbers
    e.g. -2² = 4 and not -4! Also, 9 - (4 x -1 x 6) = 9 + 24 and not 9 - 24!

c) The formula allows you to plug in values for the numbers a, b and c which appear in a     quadratic equation of the general form: ax² + bx + c. It will normally be on the formula     sheet so there should be no need to remember it.

d) Remember that all quadratic equations have two roots, hence there will always be 2
    values of x.

e) The formula is given below:

Solve the following quadratic equations giving your answers to 2 d.p.