-x^2+220x-8000=0

Solution for -x^2+220x-8000=0 equation:

-x^2+220x-8000=0

We add all the numbers together, and all the variables

-1x^2+220x-8000=0

a = -1; b = 220; c = -8000;
Δ = b2-4ac
Δ = 2202-4·(-1)·(-8000)
Δ = 16400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{16400}=\sqrt{400*41}=\sqrt{400}*\sqrt{41}=20\sqrt{41}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(220)-20\sqrt{41}}{2*-1}=\frac{-220-20\sqrt{41}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(220)+20\sqrt{41}}{2*-1}=\frac{-220+20\sqrt{41}}{-2}
$