Graphing $y=ax^2+ bx + c$ by completing the square
Add and subtract the square of half the coefficent of $x$.
Group the perfect square trinomial.
Write the trinomial as a square of a binomial.
Rewrite $y = x^2 + 6x + 8$ into $y = a(x-h)^2 + k$.
I've tried solving this but I get a bit confused at the step where I have to "write the trinomial as a square of a binomial". Not exactly sure how to do that.