20=4x*5*2x

Solution for 20=4x*5*2x equation:

20=4x*5*2x

We move all terms to the left:

20-(4x*5*2x)=0

We add all the numbers together, and all the variables

-(+4x*5*2x)+20=0

We get rid of parentheses

-4x*5*2x+20=0

Wy multiply elements

-40x^2*2+20=0

Wy multiply elements

-80x^2+20=0

a = -80; b = 0; c = +20;
Δ = b2-4ac
Δ = 02-4·(-80)·20
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-80}{2*-80}=\frac{-80}{-160}
=1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+80}{2*-80}=\frac{80}{-160}
=-1/2
$