0=1600+80x-16x^2

Solution for 0=1600+80x-16x^2 equation:

0=1600+80x-16x^2

We move all terms to the left:

0-(1600+80x-16x^2)=0

We add all the numbers together, and all the variables

-(1600+80x-16x^2)=0

We get rid of parentheses

16x^2-80x-1600=0

a = 16; b = -80; c = -1600;
Δ = b2-4ac
Δ = -802-4·16·(-1600)
Δ = 108800
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:

$\sqrt{\Delta}=\sqrt{108800}=\sqrt{6400*17}=\sqrt{6400}*\sqrt{17}=80\sqrt{17}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-80)-80\sqrt{17}}{2*16}=\frac{80-80\sqrt{17}}{32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-80)+80\sqrt{17}}{2*16}=\frac{80+80\sqrt{17}}{32}
$