20n^2-84n-80=0

Solution for 20n^2-84n-80=0 equation:

20n^2-84n-80=0

a = 20; b = -84; c = -80;
Δ = b2-4ac
Δ = -842-4·20·(-80)
Δ = 13456
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{13456}=116$
$n_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-84)-116}{2*20}=\frac{-32}{40}
=-4/5
$
$n_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-84)+116}{2*20}=\frac{200}{40}
=5
$