(x+20)(x+30)=600

Solution for (x+20)(x+30)=600 equation:

(x+20)(x+30)=600

We move all terms to the left:

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

We multiply parentheses ..

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

We get rid of parentheses

x^2+30x+20x+600-600=0

We add all the numbers together, and all the variables

x^2+50x=0

a = 1; b = 50; c = 0;
Δ = b2-4ac
Δ = 502-4·1·0
Δ = 2500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2500}=50$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-50}{2*1}=\frac{-100}{2}
=-50
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+50}{2*1}=\frac{0}{2}
=0
$