228=(20+2x)(12+2x)

Solution for 228=(20+2x)(12+2x) equation:

228=(20+2x)(12+2x)

We move all terms to the left:

228-((20+2x)(12+2x))=0

We add all the numbers together, and all the variables

-((2x+20)(2x+12))+228=0

We multiply parentheses ..

-((+4x^2+24x+40x+240))+228=0


We calculate terms in parentheses: -((+4x^2+24x+40x+240)), so:

(+4x^2+24x+40x+240)

We get rid of parentheses

4x^2+24x+40x+240

We add all the numbers together, and all the variables

4x^2+64x+240

Back to the equation:

-(4x^2+64x+240)


We get rid of parentheses

-4x^2-64x-240+228=0

We add all the numbers together, and all the variables

-4x^2-64x-12=0

a = -4; b = -64; c = -12;
Δ = b2-4ac
Δ = -642-4·(-4)·(-12)
Δ = 3904
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3904}=\sqrt{64*61}=\sqrt{64}*\sqrt{61}=8\sqrt{61}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-64)-8\sqrt{61}}{2*-4}=\frac{64-8\sqrt{61}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-64)+8\sqrt{61}}{2*-4}=\frac{64+8\sqrt{61}}{-8}
$