0=x^2+2.3x-2.1

Solution for 0=x^2+2.3x-2.1 equation:

0=x^2+2.3x-2.1

We move all terms to the left:

0-(x^2+2.3x-2.1)=0

We add all the numbers together, and all the variables

-(x^2+2.3x-2.1)=0

We get rid of parentheses

-x^2-2.3x+2.1=0

We add all the numbers together, and all the variables

-1x^2-2.3x+2.1=0

a = -1; b = -2.3; c = +2.1;
Δ = b2-4ac
Δ = -2.32-4·(-1)·2.1
Δ = 13.69
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{-(-2.3)-\sqrt{13.69}}{2*-1}=\frac{2.3-\sqrt{13.69}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2.3)+\sqrt{13.69}}{2*-1}=\frac{2.3+\sqrt{13.69}}{-2}
$