x^2-8-0,4289x=0

Solution for x^2-8-0,4289x=0 equation:

x^2-8-0.4289x=0

a = 1; b = -0.4289; c = -8;
Δ = b2-4ac
Δ = -0.42892-4·1·(-8)
Δ = 32.18395521
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{-(-0.4289)-\sqrt{32.18395521}}{2*1}=\frac{0.4289-\sqrt{32.18395521}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.4289)+\sqrt{32.18395521}}{2*1}=\frac{0.4289+\sqrt{32.18395521}}{2}
$