x^2-64x-80=0

Solution for x^2-64x-80=0 equation:

x^2-64x-80=0

a = 1; b = -64; c = -80;
Δ = b2-4ac
Δ = -642-4·1·(-80)
Δ = 4416
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:

$\sqrt{\Delta}=\sqrt{4416}=\sqrt{64*69}=\sqrt{64}*\sqrt{69}=8\sqrt{69}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-8\sqrt{69}}{2*1}=\frac{64-8\sqrt{69}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+8\sqrt{69}}{2*1}=\frac{64+8\sqrt{69}}{2}
$