x² + 5x - 104 = 0
The Quadratic Formula is a bit overkill since this quadratic is factorable, but here's how you would use the quadratic formula to solve it:
a = 1, b = 5, c = -104
x = (-b ± √(b² - 4ac))/(2a)
x = (-5 ± √(5² - 4 × 1 × -104))/(2 × 1)
x = (-5 ± √(25 + 416))/2
x = (-5 ± √441)/2
x = (-5 ± 21)/2
First Solution: (-5 + 21)/2 = 16/2 = 8
Second Solution: (-5 - 21)/2 = -26/2 = -13
So, the roots are 8 & -13. Hope this helps! :)