20x2-39x-80=0

Solution for 20x2-39x-80=0 equation:

20x^2-39x-80=0

a = 20; b = -39; c = -80;
Δ = b2-4ac
Δ = -392-4·20·(-80)
Δ = 7921
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7921}=89$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-39)-89}{2*20}=\frac{-50}{40}
=-1+1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-39)+89}{2*20}=\frac{128}{40}
=3+1/5
$