(20+x)(30+x)=336

Solution for (20+x)(30+x)=336 equation:

(20+x)(30+x)=336

We move all terms to the left:

(20+x)(30+x)-(336)=0

We add all the numbers together, and all the variables

(x+20)(x+30)-336=0

We multiply parentheses ..

(+x^2+30x+20x+600)-336=0

We get rid of parentheses

x^2+30x+20x+600-336=0

We add all the numbers together, and all the variables

x^2+50x+264=0

a = 1; b = 50; c = +264;
Δ = b2-4ac
Δ = 502-4·1·264
Δ = 1444
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1444}=38$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-38}{2*1}=\frac{-88}{2}
=-44
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+38}{2*1}=\frac{-12}{2}
=-6
$