Quadratic Equations with Complex Roots

Factorisation is the normal method of solving quadratics e.g. the big X method. But sometimes this cannot be done and the following formula can be used.
The equation has the roots given by the formula

Example

Solve the equation which is of the form therefore
a=1 b=-4 and c=13 plug this into the above equation

                                                                                                                          Exercise