0=-2.8x^2+5.6x

Solution for 0=-2.8x^2+5.6x equation:

0=-2.8x^2+5.6x

We move all terms to the left:

0-(-2.8x^2+5.6x)=0

We add all the numbers together, and all the variables

-(-2.8x^2+5.6x)=0

We get rid of parentheses

2.8x^2-5.6x=0

a = 2.8; b = -5.6; c = 0;
Δ = b2-4ac
Δ = -5.62-4·2.8·0
Δ = 31.36
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{-(-5.6)-\sqrt{31.36}}{2*2.8}=\frac{5.6-\sqrt{31.36}}{5.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5.6)+\sqrt{31.36}}{2*2.8}=\frac{5.6+\sqrt{31.36}}{5.6}
$