(0.80-x)(0.20-x)=2x

Solution for (0.80-x)(0.20-x)=2x equation:

(0.80-x)(0.20-x)=2x

We move all terms to the left:

(0.80-x)(0.20-x)-(2x)=0

We add all the numbers together, and all the variables

(-1x+0.8)(-1x+0.2)-2x=0

We add all the numbers together, and all the variables

-2x+(-1x+0.8)(-1x+0.2)=0

We multiply parentheses ..

(+x^2-0.2x-0.8x+0.16)-2x=0

We get rid of parentheses

x^2-0.2x-0.8x-2x+0.16=0

We add all the numbers together, and all the variables

x^2-3x+0.16=0

a = 1; b = -3; c = +0.16;
Δ = b2-4ac
Δ = -32-4·1·0.16
Δ = 8.36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-\sqrt{8.36}}{2*1}=\frac{3-\sqrt{8.36}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+\sqrt{8.36}}{2*1}=\frac{3+\sqrt{8.36}}{2}
$