2160=x^2+0.2x

Solution for 2160=x^2+0.2x equation:

2160=x^2+0.2x

We move all terms to the left:

2160-(x^2+0.2x)=0

We get rid of parentheses

-x^2-0.2x+2160=0

We add all the numbers together, and all the variables

-1x^2-0.2x+2160=0

a = -1; b = -0.2; c = +2160;
Δ = b2-4ac
Δ = -0.22-4·(-1)·2160
Δ = 8640.04
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{-(-0.2)-\sqrt{8640.04}}{2*-1}=\frac{0.2-\sqrt{8640.04}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.2)+\sqrt{8640.04}}{2*-1}=\frac{0.2+\sqrt{8640.04}}{-2}
$