624=(10+2x)*(30+2x)

Solution for 624=(10+2x)*(30+2x) equation:

624=(10+2x)(30+2x)

We move all terms to the left:

624-((10+2x)(30+2x))=0

We add all the numbers together, and all the variables

-((2x+10)(2x+30))+624=0

We multiply parentheses ..

-((+4x^2+60x+20x+300))+624=0


We calculate terms in parentheses: -((+4x^2+60x+20x+300)), so:

(+4x^2+60x+20x+300)

We get rid of parentheses

4x^2+60x+20x+300

We add all the numbers together, and all the variables

4x^2+80x+300

Back to the equation:

-(4x^2+80x+300)


We get rid of parentheses

-4x^2-80x-300+624=0

We add all the numbers together, and all the variables

-4x^2-80x+324=0

a = -4; b = -80; c = +324;
Δ = b2-4ac
Δ = -802-4·(-4)·324
Δ = 11584
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:

$\sqrt{\Delta}=\sqrt{11584}=\sqrt{64*181}=\sqrt{64}*\sqrt{181}=8\sqrt{181}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-80)-8\sqrt{181}}{2*-4}=\frac{80-8\sqrt{181}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-80)+8\sqrt{181}}{2*-4}=\frac{80+8\sqrt{181}}{-8}
$