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