5x^2-128x-720=0

Solution for 5x^2-128x-720=0 equation:

5x^2-128x-720=0

a = 5; b = -128; c = -720;
Δ = b2-4ac
Δ = -1282-4·5·(-720)
Δ = 30784
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:

$\sqrt{\Delta}=\sqrt{30784}=\sqrt{64*481}=\sqrt{64}*\sqrt{481}=8\sqrt{481}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-128)-8\sqrt{481}}{2*5}=\frac{128-8\sqrt{481}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-128)+8\sqrt{481}}{2*5}=\frac{128+8\sqrt{481}}{10}
$