3=-16x^2-64x

Solution for 3=-16x^2-64x equation:

3=-16x^2-64x

We move all terms to the left:

3-(-16x^2-64x)=0

We get rid of parentheses

16x^2+64x+3=0

a = 16; b = 64; c = +3;
Δ = b2-4ac
Δ = 642-4·16·3
Δ = 3904
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:

$\sqrt{\Delta}=\sqrt{3904}=\sqrt{64*61}=\sqrt{64}*\sqrt{61}=8\sqrt{61}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(64)-8\sqrt{61}}{2*16}=\frac{-64-8\sqrt{61}}{32}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(64)+8\sqrt{61}}{2*16}=\frac{-64+8\sqrt{61}}{32}
$