0=12x-0.12x^2

Solution for 0=12x-0.12x^2 equation:

0=12x-0.12x^2

We move all terms to the left:

0-(12x-0.12x^2)=0

We add all the numbers together, and all the variables

-(12x-0.12x^2)=0

We get rid of parentheses

0.12x^2-12x=0

a = 0.12; b = -12; c = 0;
Δ = b2-4ac
Δ = -122-4·0.12·0
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-12)-12}{2*0.12}=\frac{0}{0.24}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-12)+12}{2*0.12}=\frac{24}{0.24}
=100
$