0.2x^2-0.2x-0.2=0

Solution for 0.2x^2-0.2x-0.2=0 equation:

0.2x^2-0.2x-0.2=0

a = 0.2; b = -0.2; c = -0.2;
Δ = b2-4ac
Δ = -0.22-4·0.2·(-0.2)
Δ = 0.2
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{-(-0.2)-\sqrt{0.2}}{2*0.2}=\frac{0.2-\sqrt{0.2}}{0.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.2)+\sqrt{0.2}}{2*0.2}=\frac{0.2+\sqrt{0.2}}{0.4}
$