-72x^2+104x-20=0

Solution for -72x^2+104x-20=0 equation:

-72x^2+104x-20=0

a = -72; b = 104; c = -20;
Δ = b2-4ac
Δ = 1042-4·(-72)·(-20)
Δ = 5056
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:

$\sqrt{\Delta}=\sqrt{5056}=\sqrt{64*79}=\sqrt{64}*\sqrt{79}=8\sqrt{79}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(104)-8\sqrt{79}}{2*-72}=\frac{-104-8\sqrt{79}}{-144}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(104)+8\sqrt{79}}{2*-72}=\frac{-104+8\sqrt{79}}{-144}
$