0=-0.8x^2-0.06x+3.4

Solution for 0=-0.8x^2-0.06x+3.4 equation:

0=-0.8x^2-0.06x+3.4

We move all terms to the left:

0-(-0.8x^2-0.06x+3.4)=0

We add all the numbers together, and all the variables

-(-0.8x^2-0.06x+3.4)=0

We get rid of parentheses

0.8x^2+0.06x-3.4=0

a = 0.8; b = 0.06; c = -3.4;
Δ = b2-4ac
Δ = 0.062-4·0.8·(-3.4)
Δ = 10.8836
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{-(0.06)-\sqrt{10.8836}}{2*0.8}=\frac{-0.06-\sqrt{10.8836}}{1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0.06)+\sqrt{10.8836}}{2*0.8}=\frac{-0.06+\sqrt{10.8836}}{1.6}
$