X*y=20000

Solution for X*y=20000 equation:

X*X=20000

We move all terms to the left:

X*X-(20000)=0

Wy multiply elements

X^2-20000=0

a = 1; b = 0; c = -20000;
Δ = b2-4ac
Δ = 02-4·1·(-20000)
Δ = 80000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{80000}=\sqrt{40000*2}=\sqrt{40000}*\sqrt{2}=200\sqrt{2}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-200\sqrt{2}}{2*1}=\frac{0-200\sqrt{2}}{2}
=-\frac{200\sqrt{2}}{2}
=-100\sqrt{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+200\sqrt{2}}{2*1}=\frac{0+200\sqrt{2}}{2}
=\frac{200\sqrt{2}}{2}
=100\sqrt{2}
$