392=x*(x/2)

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

392=x*(x/2)

We move all terms to the left:

392-(x*(x/2))=0

We add all the numbers together, and all the variables

-(x*(+x/2))+392=0

We multiply all the terms by the denominator


-(x*(+x+392*2))=0


We calculate terms in parentheses: -(x*(+x+392*2)), so:

x*(+x+392*2)

We add all the numbers together, and all the variables

x*(x+784)

We multiply parentheses

x^2+784x

Back to the equation:

-(x^2+784x)


We get rid of parentheses

-x^2-784x=0

We add all the numbers together, and all the variables

-1x^2-784x=0

a = -1; b = -784; c = 0;
Δ = b2-4ac
Δ = -7842-4·(-1)·0
Δ = 614656
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{614656}=784$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-784)-784}{2*-1}=\frac{0}{-2}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-784)+784}{2*-1}=\frac{1568}{-2}
=-784
$