840=(x-8)(x-12)6

Solution for 840=(x-8)(x-12)6 equation:

840=(x-8)(x-12)6

We move all terms to the left:

840-((x-8)(x-12)6)=0

We multiply parentheses ..

-((+x^2-12x-8x+96)6)+840=0


We calculate terms in parentheses: -((+x^2-12x-8x+96)6), so:

(+x^2-12x-8x+96)6

We multiply parentheses

6x^2-72x-48x+576

We add all the numbers together, and all the variables

6x^2-120x+576

Back to the equation:

-(6x^2-120x+576)


We get rid of parentheses

-6x^2+120x-576+840=0

We add all the numbers together, and all the variables

-6x^2+120x+264=0

a = -6; b = 120; c = +264;
Δ = b2-4ac
Δ = 1202-4·(-6)·264
Δ = 20736
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{20736}=144$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(120)-144}{2*-6}=\frac{-264}{-12}
=+22
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(120)+144}{2*-6}=\frac{24}{-12}
=-2
$