20x^2-30x-80=0

Solution for 20x^2-30x-80=0 equation:

20x^2-30x-80=0

a = 20; b = -30; c = -80;
Δ = b2-4ac
Δ = -302-4·20·(-80)
Δ = 7300
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{7300}=\sqrt{100*73}=\sqrt{100}*\sqrt{73}=10\sqrt{73}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-10\sqrt{73}}{2*20}=\frac{30-10\sqrt{73}}{40}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+10\sqrt{73}}{2*20}=\frac{30+10\sqrt{73}}{40}
$