How do solve this quadratic equation

5x(squared)+13x-1=0 USING THE QUADRATIC FORMULA
please show answers too
thank you!

http://www.mathwarehouse.com/quadratic/quadratic-formula-calculator.php

Quadratic equation calculater online. Merry christmas.

5x^2 + 13x - 1 = 0

a = 5
b = 13
c = - 1

x = (- b +- sqrt(b^2 - 4ac))/2a

x = (- 13 +- sqrt(169 - 4(20)(- 1))/10

x = (- 13 +- sqrt(169 + 80))/10

x = (- 13 +- sqrt(249))/10

x = (- 13 +- 15.78)/2

x = - 6.5 +- 7.89

x = 1.39 or x = - 14.39