This website is going to explain to you how to use the quadratic formula to find roots. Using five links that will take you to five websites defining the topic on top of the page.
The following website below shows the quadratic formula with polynomials using second degree.
http://www.web-formulas.com/Math_Formulas/Algebra_Polynomials_Second_Degree.aspx
http://www.web-formulas.com/Math_Formulas/Algebra_Polynomials_Second_Degree.aspx
The following website below has the quadratic formula showing how to find root in a equation.
http://www.teacherschoice.com.au/maths_library/algebra/alg_6.htm
http://www.teacherschoice.com.au/maths_library/algebra/alg_6.htm
The following website explains how to do the quadratic formula with polynomials. At the end its shows how to use roots with polynomials involve.
http://www.sosmath.com/algebra/factor/fac08/fac08.html
http://www.sosmath.com/algebra/factor/fac08/fac08.html
The follwoing website below has all nine steps of the quadratic formula. It doesn't only dervive the quadratic formula itself, but also using roots.
http://www.wyzant.com/Help/Math/Algebra/Quadratic_Formula.aspx
http://www.wyzant.com/Help/Math/Algebra/Quadratic_Formula.aspx
This following website below it has some examples on how roots are solved. It gives a clearer understanding if you will be solving the quadratic formula using roots. Step by step
http://oregonstate.edu/instruct/mth251/cq/FieldGuide/polynomial/more.html
http://oregonstate.edu/instruct/mth251/cq/FieldGuide/polynomial/more.html