0,3x^2=2,1x

Solution for 0,3x^2=2,1x equation:

0.3x^2=2.1x

We move all terms to the left:

0.3x^2-(2.1x)=0

We add all the numbers together, and all the variables

0.3x^2-(+2.1x)=0

We get rid of parentheses

0.3x^2-2.1x=0

a = 0.3; b = -2.1; c = 0;
Δ = b2-4ac
Δ = -2.12-4·0.3·0
Δ = 4.41
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{-(-2.1)-\sqrt{4.41}}{2*0.3}=\frac{2.1-\sqrt{4.41}}{0.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2.1)+\sqrt{4.41}}{2*0.3}=\frac{2.1+\sqrt{4.41}}{0.6}
$