-5x^2+72x-220=0

Solution for -5x^2+72x-220=0 equation:

-5x^2+72x-220=0

a = -5; b = 72; c = -220;
Δ = b2-4ac
Δ = 722-4·(-5)·(-220)
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(72)-28}{2*-5}=\frac{-100}{-10}
=+10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(72)+28}{2*-5}=\frac{-44}{-10}
=4+2/5
$