-2x^2+24x-40=0

Solution for -2x^2+24x-40=0 equation:

-2x^2+24x-40=0

a = -2; b = 24; c = -40;
Δ = b2-4ac
Δ = 242-4·(-2)·(-40)
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(24)-16}{2*-2}=\frac{-40}{-4}
=+10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(24)+16}{2*-2}=\frac{-8}{-4}
=+2
$