-3x^2-20x+1600=0

Solution for -3x^2-20x+1600=0 equation:

-3x^2-20x+1600=0

a = -3; b = -20; c = +1600;
Δ = b2-4ac
Δ = -202-4·(-3)·1600
Δ = 19600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{19600}=140$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-140}{2*-3}=\frac{-120}{-6}
=+20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+140}{2*-3}=\frac{160}{-6}
=-26+2/3
$