X(x/2)=392

Solution for X(x/2)=392 equation:

X(X/2)=392

We move all terms to the left:

X(X/2)-(392)=0

We add all the numbers together, and all the variables

X(+X/2)-392=0

We multiply parentheses

X^2-392=0

a = 1; b = 0; c = -392;
Δ = b2-4ac
Δ = 02-4·1·(-392)
Δ = 1568
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1568}=\sqrt{784*2}=\sqrt{784}*\sqrt{2}=28\sqrt{2}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-28\sqrt{2}}{2*1}=\frac{0-28\sqrt{2}}{2}
=-\frac{28\sqrt{2}}{2}
=-14\sqrt{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+28\sqrt{2}}{2*1}=\frac{0+28\sqrt{2}}{2}
=\frac{28\sqrt{2}}{2}
=14\sqrt{2}
$