-16x^2+40x+240=0

Solution for -16x^2+40x+240=0 equation:

-16x^2+40x+240=0

a = -16; b = 40; c = +240;
Δ = b2-4ac
Δ = 402-4·(-16)·240
Δ = 16960
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:

$\sqrt{\Delta}=\sqrt{16960}=\sqrt{64*265}=\sqrt{64}*\sqrt{265}=8\sqrt{265}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-8\sqrt{265}}{2*-16}=\frac{-40-8\sqrt{265}}{-32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+8\sqrt{265}}{2*-16}=\frac{-40+8\sqrt{265}}{-32}
$