(2x+8)(2x+12)=12

Solution for (2x+8)(2x+12)=12 equation:

(2x+8)(2x+12)=12

We move all terms to the left:

(2x+8)(2x+12)-(12)=0

We multiply parentheses ..

(+4x^2+24x+16x+96)-12=0

We get rid of parentheses

4x^2+24x+16x+96-12=0

We add all the numbers together, and all the variables

4x^2+40x+84=0

a = 4; b = 40; c = +84;
Δ = b2-4ac
Δ = 402-4·4·84
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-16}{2*4}=\frac{-56}{8}
=-7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+16}{2*4}=\frac{-24}{8}
=-3
$