20x^2+419x-21=0

Solution for 20x^2+419x-21=0 equation:

20x^2+419x-21=0

a = 20; b = 419; c = -21;
Δ = b2-4ac
Δ = 4192-4·20·(-21)
Δ = 177241
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{177241}=421$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(419)-421}{2*20}=\frac{-840}{40}
=-21
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(419)+421}{2*20}=\frac{2}{40}
=1/20
$