-16X^2+40x+56=0

Solution for -16X^2+40x+56=0 equation:

-16X^2+40X+56=0

a = -16; b = 40; c = +56;
Δ = b2-4ac
Δ = 402-4·(-16)·56
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-72}{2*-16}=\frac{-112}{-32}
=3+1/2
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+72}{2*-16}=\frac{32}{-32}
=-1
$