Question 555668
Do you mean "How do you complete the square?"
I do not really know what you meant to ask, but I am going to try to answer, anyway.
{{{x^2+x-6}}} has 3 terms, so it is a trinomial.
It's degree is 2, so it can be called a quadratic trinomial, or a quadratic polynomial.
{{{f(x)=x^2+x-6}}} would be called a quadratic function, and
{{{x^2+x-6=0}}} would be called a quadratic equation.
The sum of terms {{{x^2+x}}} can be considered to be part of the square
{{{(x+1/2)^2=x^2+x+1/4}}}
That trick is often called "completing the square."
That is useful for finding the axis of symmetry and vertex of the curve (called a parabola) described by {{{f(x)=x^2+x-6}}}.
It is also useful for solving quadratic equations.
{{{f(x)=x^2+x-6=x^2+x+1/4-1/4-6=(x+1/2)^2-25/4}}}
That tells you that the function has a minimum (and the parabola has a vertex) at
{{{x=-1/2}}} with {{{f(-1/2)=-25/4}}} 
Similarly {{{x^2+x-6=0}}} can be written as
{{{(x+1/2)^2-25/4=0}}} or {{{(x+1/2)^2=25/4}}} and solved to get
{{{x=-1/2 +- sqrt(25/4)=-1/2 +- 5/2}}} , which gives you {{{x=2}}} and {{{x=-3}}} as solutions.