240=(2x+30)(2x+26)

Solution for 240=(2x+30)(2x+26) equation:

240=(2x+30)(2x+26)

We move all terms to the left:

240-((2x+30)(2x+26))=0

We multiply parentheses ..

-((+4x^2+52x+60x+780))+240=0


We calculate terms in parentheses: -((+4x^2+52x+60x+780)), so:

(+4x^2+52x+60x+780)

We get rid of parentheses

4x^2+52x+60x+780

We add all the numbers together, and all the variables

4x^2+112x+780

Back to the equation:

-(4x^2+112x+780)


We get rid of parentheses

-4x^2-112x-780+240=0

We add all the numbers together, and all the variables

-4x^2-112x-540=0

a = -4; b = -112; c = -540;
Δ = b2-4ac
Δ = -1122-4·(-4)·(-540)
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{-(-112)-8\sqrt{61}}{2*-4}=\frac{112-8\sqrt{61}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-112)+8\sqrt{61}}{2*-4}=\frac{112+8\sqrt{61}}{-8}
$