0=20+4x-16x^2

Solution for 0=20+4x-16x^2 equation:

0=20+4x-16x^2

We move all terms to the left:

0-(20+4x-16x^2)=0

We add all the numbers together, and all the variables

-(20+4x-16x^2)=0

We get rid of parentheses

16x^2-4x-20=0

a = 16; b = -4; c = -20;
Δ = b2-4ac
Δ = -42-4·16·(-20)
Δ = 1296
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1296}=36$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-36}{2*16}=\frac{-32}{32}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+36}{2*16}=\frac{40}{32}
=1+1/4
$