0=1800+250x-3x^2

Solution for 0=1800+250x-3x^2 equation:

0=1800+250x-3x^2

We move all terms to the left:

0-(1800+250x-3x^2)=0

We add all the numbers together, and all the variables

-(1800+250x-3x^2)=0

We get rid of parentheses

3x^2-250x-1800=0

a = 3; b = -250; c = -1800;
Δ = b2-4ac
Δ = -2502-4·3·(-1800)
Δ = 84100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{84100}=290$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-250)-290}{2*3}=\frac{-40}{6}
=-6+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-250)+290}{2*3}=\frac{540}{6}
=90
$