x^2-40x-480=0

Solution for x^2-40x-480=0 equation:

x^2-40x-480=0

a = 1; b = -40; c = -480;
Δ = b2-4ac
Δ = -402-4·1·(-480)
Δ = 3520
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:

$\sqrt{\Delta}=\sqrt{3520}=\sqrt{64*55}=\sqrt{64}*\sqrt{55}=8\sqrt{55}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-8\sqrt{55}}{2*1}=\frac{40-8\sqrt{55}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+8\sqrt{55}}{2*1}=\frac{40+8\sqrt{55}}{2}
$