0.5x+0.8x^2=0

Solution for 0.5x+0.8x^2=0 equation:

0.5x+0.8x^2=0

a = 0.8; b = 0.5; c = 0;
Δ = b2-4ac
Δ = 0.52-4·0.8·0
Δ = 0.25
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{-(0.5)-\sqrt{0.25}}{2*0.8}=\frac{-0.5-\sqrt{0.25}}{1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.5)+\sqrt{0.25}}{2*0.8}=\frac{-0.5+\sqrt{0.25}}{1.6}
$