x+0.2x=0.2x2

Solution for x+0.2x=0.2x2 equation:

x+0.2x=0.2x^2

We move all terms to the left:

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

We add all the numbers together, and all the variables

1.2x-(0.2x^2)=0

We get rid of parentheses

-0.2x^2+1.2x=0

a = -0.2; b = 1.2; c = 0;
Δ = b2-4ac
Δ = 1.22-4·(-0.2)·0
Δ = 1.44
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{-(1.2)-\sqrt{1.44}}{2*-0.2}=\frac{-1.2-\sqrt{1.44}}{-0.4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1.2)+\sqrt{1.44}}{2*-0.2}=\frac{-1.2+\sqrt{1.44}}{-0.4}
$