0=15000-300x^2

Solution for 0=15000-300x^2 equation:

0=15000-300x^2

We move all terms to the left:

0-(15000-300x^2)=0

We add all the numbers together, and all the variables

-(15000-300x^2)=0

We get rid of parentheses

300x^2-15000=0

a = 300; b = 0; c = -15000;
Δ = b2-4ac
Δ = 02-4·300·(-15000)
Δ = 18000000
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:

$\sqrt{\Delta}=\sqrt{18000000}=\sqrt{9000000*2}=\sqrt{9000000}*\sqrt{2}=3000\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-3000\sqrt{2}}{2*300}=\frac{0-3000\sqrt{2}}{600}
=-\frac{3000\sqrt{2}}{600}
=-5\sqrt{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+3000\sqrt{2}}{2*300}=\frac{0+3000\sqrt{2}}{600}
=\frac{3000\sqrt{2}}{600}
=5\sqrt{2}
$