0=330x-9000-x^2

Solution for 0=330x-9000-x^2 equation:

0=330x-9000-x^2

We move all terms to the left:

0-(330x-9000-x^2)=0

We add all the numbers together, and all the variables

-(330x-9000-x^2)=0

We get rid of parentheses

x^2-330x+9000=0

a = 1; b = -330; c = +9000;
Δ = b2-4ac
Δ = -3302-4·1·9000
Δ = 72900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{72900}=270$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-330)-270}{2*1}=\frac{60}{2}
=30
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-330)+270}{2*1}=\frac{600}{2}
=300
$