(x*0.1)x=200

Solution for (x*0.1)x=200 equation:

(x*0.1)x=200

We move all terms to the left:

(x*0.1)x-(200)=0

We add all the numbers together, and all the variables

(+x*0.1)x-200=0

We multiply parentheses

0.1x^2-200=0

a = 0.1; b = 0; c = -200;
Δ = b2-4ac
Δ = 02-4·0.1·(-200)
Δ = 80
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{80}=\sqrt{16*5}=\sqrt{16}*\sqrt{5}=4\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{5}}{2*0.1}=\frac{0-4\sqrt{5}}{0.2}
=-\frac{4\sqrt{5}}{0.2}
=-\frac{\sqrt{5}}{0.05}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{5}}{2*0.1}=\frac{0+4\sqrt{5}}{0.2}
=\frac{4\sqrt{5}}{0.2}
=\frac{\sqrt{5}}{0.05}
$