x^2-40x-800=0

Solution for x^2-40x-800=0 equation:

x^2-40x-800=0

a = 1; b = -40; c = -800;
Δ = b2-4ac
Δ = -402-4·1·(-800)
Δ = 4800
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:

$\sqrt{\Delta}=\sqrt{4800}=\sqrt{1600*3}=\sqrt{1600}*\sqrt{3}=40\sqrt{3}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-40\sqrt{3}}{2*1}=\frac{40-40\sqrt{3}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+40\sqrt{3}}{2*1}=\frac{40+40\sqrt{3}}{2}
$