n^2+n-2*820=0

Solution for n^2+n-2*820=0 equation:

n^2+n-2*820=0

We add all the numbers together, and all the variables

n^2+n-1640=0

a = 1; b = 1; c = -1640;
Δ = b2-4ac
Δ = 12-4·1·(-1640)
Δ = 6561
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6561}=81$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-81}{2*1}=\frac{-82}{2}
=-41
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+81}{2*1}=\frac{80}{2}
=40
$