50=-16x^2+128x

Solution for 50=-16x^2+128x equation:

50=-16x^2+128x

We move all terms to the left:

50-(-16x^2+128x)=0

We get rid of parentheses

16x^2-128x+50=0

a = 16; b = -128; c = +50;
Δ = b2-4ac
Δ = -1282-4·16·50
Δ = 13184
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:

$\sqrt{\Delta}=\sqrt{13184}=\sqrt{64*206}=\sqrt{64}*\sqrt{206}=8\sqrt{206}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-128)-8\sqrt{206}}{2*16}=\frac{128-8\sqrt{206}}{32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-128)+8\sqrt{206}}{2*16}=\frac{128+8\sqrt{206}}{32}
$