Question 823356
You usually are given the equation {{{ax^2+bx+c=0}}}.
The first thing you do is take half of b and square it {{{(b/2)^2}}}.  Then you add this to both sides. {{{ax^2+bx+c+(b/2)^2=(b/2)^2}}}.
When you factor it you would get {{{(x+(b/2))^2+c=(b/2)^2}}}.  Then you would move  the {{{(b/2)^2}}} to the left side.
{{{(x+(b/2))^2+c-(b/2)^2=0}}}


example:
{{{x^2+8x+3=0}}}
take half of 8 and square it, then add this number to both sides of the equation.
{{{x^2+8x+16+3=16}}}
This becomes {{{(x+4)^2+3=16}}}
Then move the 16 to the left side
{{{(x+4)^2-13=0}}}