168=(2x+10)(2x+8)

Solution for 168=(2x+10)(2x+8) equation:

168=(2x+10)(2x+8)

We move all terms to the left:

168-((2x+10)(2x+8))=0

We multiply parentheses ..

-((+4x^2+16x+20x+80))+168=0


We calculate terms in parentheses: -((+4x^2+16x+20x+80)), so:

(+4x^2+16x+20x+80)

We get rid of parentheses

4x^2+16x+20x+80

We add all the numbers together, and all the variables

4x^2+36x+80

Back to the equation:

-(4x^2+36x+80)


We get rid of parentheses

-4x^2-36x-80+168=0

We add all the numbers together, and all the variables

-4x^2-36x+88=0

a = -4; b = -36; c = +88;
Δ = b2-4ac
Δ = -362-4·(-4)·88
Δ = 2704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2704}=52$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-36)-52}{2*-4}=\frac{-16}{-8}
=+2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-36)+52}{2*-4}=\frac{88}{-8}
=-11
$