x^2-1,8x+0,81=0,25

Solution for x^2-1,8x+0,81=0,25 equation:

x^2-1.8x+0.81=0.25

We move all terms to the left:

x^2-1.8x+0.81-(0.25)=0

We add all the numbers together, and all the variables

x^2-1.8x+0.56=0

a = 1; b = -1.8; c = +0.56;
Δ = b2-4ac
Δ = -1.82-4·1·0.56
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1.8)-1}{2*1}=\frac{0.8}{2}
=0.8/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.8)+1}{2*1}=\frac{2.8}{2}
=1+0.8/2
$