40,500=30x-0.002x2

Solution for 40,500=30x-0.002x2 equation:

40.500=30x-0.002x^2

We move all terms to the left:

40.500-(30x-0.002x^2)=0

We add all the numbers together, and all the variables

-(30x-0.002x^2)+40.5=0

We get rid of parentheses

0.002x^2-30x+40.5=0

a = 0.002; b = -30; c = +40.5;
Δ = b2-4ac
Δ = -302-4·0.002·40.5
Δ = 899.676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-\sqrt{899.676}}{2*0.002}=\frac{30-\sqrt{899.676}}{0.004}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+\sqrt{899.676}}{2*0.002}=\frac{30+\sqrt{899.676}}{0.004}
$