0,902+2,38x-0,0399x^2=0

Solution for 0,902+2,38x-0,0399x^2=0 equation:

0.902+2.38x-0.0399x^2=0

a = -0.0399; b = 2.38; c = +0.902;
Δ = b2-4ac
Δ = 2.382-4·(-0.0399)·0.902
Δ = 5.8083592
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{-(2.38)-\sqrt{5.8083592}}{2*-0.0399}=\frac{-2.38-\sqrt{5.8083592}}{-0.0798}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.38)+\sqrt{5.8083592}}{2*-0.0399}=\frac{-2.38+\sqrt{5.8083592}}{-0.0798}
$