0=-0.33x^2+0.84x+6

Solution for 0=-0.33x^2+0.84x+6 equation:

0=-0.33x^2+0.84x+6

We move all terms to the left:

0-(-0.33x^2+0.84x+6)=0

We add all the numbers together, and all the variables

-(-0.33x^2+0.84x+6)=0

We get rid of parentheses

0.33x^2-0.84x-6=0

a = 0.33; b = -0.84; c = -6;
Δ = b2-4ac
Δ = -0.842-4·0.33·(-6)
Δ = 8.6256
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{-(-0.84)-\sqrt{8.6256}}{2*0.33}=\frac{0.84-\sqrt{8.6256}}{0.66}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.84)+\sqrt{8.6256}}{2*0.33}=\frac{0.84+\sqrt{8.6256}}{0.66}
$