400x^2=4-2x-2x+x^2

Solution for 400x^2=4-2x-2x+x^2 equation:

400x^2=4-2x-2x+x^2

We move all terms to the left:

400x^2-(4-2x-2x+x^2)=0

We get rid of parentheses

400x^2-x^2+2x+2x-4=0

We add all the numbers together, and all the variables

399x^2+4x-4=0

a = 399; b = 4; c = -4;
Δ = b2-4ac
Δ = 42-4·399·(-4)
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-80}{2*399}=\frac{-84}{798}
=-2/19
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+80}{2*399}=\frac{76}{798}
=2/21
$