5x^2-80x-64=0

Solution for 5x^2-80x-64=0 equation:

5x^2-80x-64=0

a = 5; b = -80; c = -64;
Δ = b2-4ac
Δ = -802-4·5·(-64)
Δ = 7680
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:

$\sqrt{\Delta}=\sqrt{7680}=\sqrt{256*30}=\sqrt{256}*\sqrt{30}=16\sqrt{30}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-80)-16\sqrt{30}}{2*5}=\frac{80-16\sqrt{30}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-80)+16\sqrt{30}}{2*5}=\frac{80+16\sqrt{30}}{10}
$