x^2+1.6x=0.8

Solution for x^2+1.6x=0.8 equation:

x^2+1.6x=0.8

We move all terms to the left:

x^2+1.6x-(0.8)=0

We add all the numbers together, and all the variables

x^2+1.6x-0.8=0

a = 1; b = 1.6; c = -0.8;
Δ = b2-4ac
Δ = 1.62-4·1·(-0.8)
Δ = 5.76
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{-(1.6)-\sqrt{5.76}}{2*1}=\frac{-1.6-\sqrt{5.76}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.6)+\sqrt{5.76}}{2*1}=\frac{-1.6+\sqrt{5.76}}{2}
$