x^2-16x-20736=0

Solution for x^2-16x-20736=0 equation:

x^2-16x-20736=0

a = 1; b = -16; c = -20736;
Δ = b2-4ac
Δ = -162-4·1·(-20736)
Δ = 83200
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:

$\sqrt{\Delta}=\sqrt{83200}=\sqrt{6400*13}=\sqrt{6400}*\sqrt{13}=80\sqrt{13}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-80\sqrt{13}}{2*1}=\frac{16-80\sqrt{13}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+80\sqrt{13}}{2*1}=\frac{16+80\sqrt{13}}{2}
$