0=-0.0005x^2+1.2345x-2.2

Solution for 0=-0.0005x^2+1.2345x-2.2 equation:

0=-0.0005x^2+1.2345x-2.2

We move all terms to the left:

0-(-0.0005x^2+1.2345x-2.2)=0

We add all the numbers together, and all the variables

-(-0.0005x^2+1.2345x-2.2)=0

We get rid of parentheses

0.0005x^2-1.2345x+2.2=0

a = 0.0005; b = -1.2345; c = +2.2;
Δ = b2-4ac
Δ = -1.23452-4·0.0005·2.2
Δ = 1.51959025
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{-(-1.2345)-\sqrt{1.51959025}}{2*0.0005}=\frac{1.2345-\sqrt{1.51959025}}{0.001}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.2345)+\sqrt{1.51959025}}{2*0.0005}=\frac{1.2345+\sqrt{1.51959025}}{0.001}
$