x^2-4.3x+2.1=0

Solution for x^2-4.3x+2.1=0 equation:

x^2-4.3x+2.1=0

a = 1; b = -4.3; c = +2.1;
Δ = b2-4ac
Δ = -4.32-4·1·2.1
Δ = 10.09
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{-(-4.3)-\sqrt{10.09}}{2*1}=\frac{4.3-\sqrt{10.09}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4.3)+\sqrt{10.09}}{2*1}=\frac{4.3+\sqrt{10.09}}{2}
$