i have a worked problem with solution, but need to check.

$\displaystyle 3x^2+2x-8=0$

$\displaystyle 3x^2+2x=8$

$\displaystyle

x^2+\frac{2x}{3}=\frac{8}{3}

$

now i must take half coefficient of x and square,right?

the next step i have been given is

$\displaystyle

x^2+\frac{2x}{3}+\frac{1}{4}=\frac{8}{3}+\frac{1}{ 4}

$

but i cannot see where the 1/4 is coming from?

as 2x/3 divided by 1/2 = 1/3?

thanks