2(x+15)(x+5)=4x+40

Solution for 2(x+15)(x+5)=4x+40 equation:

2(x+15)(x+5)=4x+40

We move all terms to the left:

2(x+15)(x+5)-(4x+40)=0

We get rid of parentheses

2(x+15)(x+5)-4x-40=0

We multiply parentheses ..

2(+x^2+5x+15x+75)-4x-40=0

We multiply parentheses

2x^2+10x+30x-4x+150-40=0

We add all the numbers together, and all the variables

2x^2+36x+110=0

a = 2; b = 36; c = +110;
Δ = b2-4ac
Δ = 362-4·2·110
Δ = 416
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:

$\sqrt{\Delta}=\sqrt{416}=\sqrt{16*26}=\sqrt{16}*\sqrt{26}=4\sqrt{26}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(36)-4\sqrt{26}}{2*2}=\frac{-36-4\sqrt{26}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(36)+4\sqrt{26}}{2*2}=\frac{-36+4\sqrt{26}}{4}
$