(1-x)*(1-x)=0.2

Solution for (1-x)*(1-x)=0.2 equation:

(1-x)(1-x)=0.2

We move all terms to the left:

(1-x)(1-x)-(0.2)=0

We add all the numbers together, and all the variables

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

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

We get rid of parentheses

x^2-1x-1x+1-0.2=0

We add all the numbers together, and all the variables

x^2-2x+0.8=0

a = 1; b = -2; c = +0.8;
Δ = b2-4ac
Δ = -22-4·1·0.8
Δ = 0.8
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{-(-2)-\sqrt{0.8}}{2*1}=\frac{2-\sqrt{0.8}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+\sqrt{0.8}}{2*1}=\frac{2+\sqrt{0.8}}{2}
$