(X+6)(x-8)=680

Solution for (X+6)(x-8)=680 equation:

(X+6)(X-8)=680

We move all terms to the left:

(X+6)(X-8)-(680)=0

We multiply parentheses ..

(+X^2-8X+6X-48)-680=0

We get rid of parentheses

X^2-8X+6X-48-680=0

We add all the numbers together, and all the variables

X^2-2X-728=0

a = 1; b = -2; c = -728;
Δ = b2-4ac
Δ = -22-4·1·(-728)
Δ = 2916
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2916}=54$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-54}{2*1}=\frac{-52}{2}
=-26
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+54}{2*1}=\frac{56}{2}
=28
$