0=-16x^2+56x+120

Solution for 0=-16x^2+56x+120 equation:

0=-16x^2+56x+120

We move all terms to the left:

0-(-16x^2+56x+120)=0

We add all the numbers together, and all the variables

-(-16x^2+56x+120)=0

We get rid of parentheses

16x^2-56x-120=0

a = 16; b = -56; c = -120;
Δ = b2-4ac
Δ = -562-4·16·(-120)
Δ = 10816
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{10816}=104$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-56)-104}{2*16}=\frac{-48}{32}
=-1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-56)+104}{2*16}=\frac{160}{32}
=5
$