x=2100x-21x^2

Solution for x=2100x-21x^2 equation:

x=2100x-21x^2

We move all terms to the left:

x-(2100x-21x^2)=0

We get rid of parentheses

21x^2-2100x+x=0

We add all the numbers together, and all the variables

21x^2-2099x=0

a = 21; b = -2099; c = 0;
Δ = b2-4ac
Δ = -20992-4·21·0
Δ = 4405801
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4405801}=2099$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2099)-2099}{2*21}=\frac{0}{42}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2099)+2099}{2*21}=\frac{4198}{42}
=99+20/21
$