x2+0.8x+0.15=0

Solution for x2+0.8x+0.15=0 equation:

x2+0.8x+0.15=0

We add all the numbers together, and all the variables

x^2+0.8x+0.15=0

a = 1; b = 0.8; c = +0.15;
Δ = b2-4ac
Δ = 0.82-4·1·0.15
Δ = 0.04
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{-(0.8)-\sqrt{0.04}}{2*1}=\frac{-0.8-\sqrt{0.04}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.8)+\sqrt{0.04}}{2*1}=\frac{-0.8+\sqrt{0.04}}{2}
$