X(x-2)=168

Solution for X(x-2)=168 equation:

X(X-2)=168

We move all terms to the left:

X(X-2)-(168)=0

We multiply parentheses

X^2-2X-168=0

a = 1; b = -2; c = -168;
Δ = b2-4ac
Δ = -22-4·1·(-168)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-26}{2*1}=\frac{-24}{2}
=-12
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+26}{2*1}=\frac{28}{2}
=14
$