810000=4x^2

Solution for 810000=4x^2 equation:

810000=4x^2

We move all terms to the left:

810000-(4x^2)=0

a = -4; b = 0; c = +810000;
Δ = b2-4ac
Δ = 02-4·(-4)·810000
Δ = 12960000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{12960000}=3600$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-3600}{2*-4}=\frac{-3600}{-8}
=+450
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+3600}{2*-4}=\frac{3600}{-8}
=-450
$