A=x(500-3x)

Solution for A=x(500-3x) equation:

=A(500-3A)

We move all terms to the left:

-(A(500-3A))=0

We add all the numbers together, and all the variables

-(A(-3A+500))=0


We calculate terms in parentheses: -(A(-3A+500)), so:

A(-3A+500)

We multiply parentheses

-3A^2+500A

Back to the equation:

-(-3A^2+500A)


We get rid of parentheses

3A^2-500A=0

a = 3; b = -500; c = 0;
Δ = b2-4ac
Δ = -5002-4·3·0
Δ = 250000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{250000}=500$
$A_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-500)-500}{2*3}=\frac{0}{6}
=0
$
$A_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-500)+500}{2*3}=\frac{1000}{6}
=166+2/3
$