(30-2x)(20-2x)=600

Solution for (30-2x)(20-2x)=600 equation:

(30-2x)(20-2x)=600

We move all terms to the left:

(30-2x)(20-2x)-(600)=0

We add all the numbers together, and all the variables

(-2x+30)(-2x+20)-600=0

We multiply parentheses ..

(+4x^2-40x-60x+600)-600=0

We get rid of parentheses

4x^2-40x-60x+600-600=0

We add all the numbers together, and all the variables

4x^2-100x=0

a = 4; b = -100; c = 0;
Δ = b2-4ac
Δ = -1002-4·4·0
Δ = 10000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{10000}=100$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-100)-100}{2*4}=\frac{0}{8}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-100)+100}{2*4}=\frac{200}{8}
=25
$