360=(20+2x)(16+2x)

Solution for 360=(20+2x)(16+2x) equation:

360=(20+2x)(16+2x)

We move all terms to the left:

360-((20+2x)(16+2x))=0

We add all the numbers together, and all the variables

-((2x+20)(2x+16))+360=0

We multiply parentheses ..

-((+4x^2+32x+40x+320))+360=0


We calculate terms in parentheses: -((+4x^2+32x+40x+320)), so:

(+4x^2+32x+40x+320)

We get rid of parentheses

4x^2+32x+40x+320

We add all the numbers together, and all the variables

4x^2+72x+320

Back to the equation:

-(4x^2+72x+320)


We get rid of parentheses

-4x^2-72x-320+360=0

We add all the numbers together, and all the variables

-4x^2-72x+40=0

a = -4; b = -72; c = +40;
Δ = b2-4ac
Δ = -722-4·(-4)·40
Δ = 5824
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:

$\sqrt{\Delta}=\sqrt{5824}=\sqrt{64*91}=\sqrt{64}*\sqrt{91}=8\sqrt{91}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-72)-8\sqrt{91}}{2*-4}=\frac{72-8\sqrt{91}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-72)+8\sqrt{91}}{2*-4}=\frac{72+8\sqrt{91}}{-8}
$