8=-16x^2+64x+6

Solution for 8=-16x^2+64x+6 equation:

8=-16x^2+64x+6

We move all terms to the left:

8-(-16x^2+64x+6)=0

We get rid of parentheses

16x^2-64x-6+8=0

We add all the numbers together, and all the variables

16x^2-64x+2=0

a = 16; b = -64; c = +2;
Δ = b2-4ac
Δ = -642-4·16·2
Δ = 3968
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:

$\sqrt{\Delta}=\sqrt{3968}=\sqrt{64*62}=\sqrt{64}*\sqrt{62}=8\sqrt{62}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-8\sqrt{62}}{2*16}=\frac{64-8\sqrt{62}}{32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+8\sqrt{62}}{2*16}=\frac{64+8\sqrt{62}}{32}
$