-0.4x^2-0.2x+1=0

Solution for -0.4x^2-0.2x+1=0 equation:

-0.4x^2-0.2x+1=0

a = -0.4; b = -0.2; c = +1;
Δ = b2-4ac
Δ = -0.22-4·(-0.4)·1
Δ = 1.64
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{1.64}}{2*-0.4}=\frac{0.2-\sqrt{1.64}}{-0.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.2)+\sqrt{1.64}}{2*-0.4}=\frac{0.2+\sqrt{1.64}}{-0.8}
$