770=-16x^2+256x

Solution for 770=-16x^2+256x equation:

770=-16x^2+256x

We move all terms to the left:

770-(-16x^2+256x)=0

We get rid of parentheses

16x^2-256x+770=0

a = 16; b = -256; c = +770;
Δ = b2-4ac
Δ = -2562-4·16·770
Δ = 16256
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:

$\sqrt{\Delta}=\sqrt{16256}=\sqrt{64*254}=\sqrt{64}*\sqrt{254}=8\sqrt{254}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-256)-8\sqrt{254}}{2*16}=\frac{256-8\sqrt{254}}{32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-256)+8\sqrt{254}}{2*16}=\frac{256+8\sqrt{254}}{32}
$