Start with a quadratic expression in the form (ax^2 + bx + c)
If (a neq 1), factor out (a) from the (x^2) and (x) terms
Take half of the coefficient of (x)
Square that half
Add and subtract that square inside the expression
Rewrite the first three terms as a perfect square trinomial
Factor the perfect square trinomial into ((x + p)^2)
Simplify the remaining constant terms
Write the result in vertex form (a(x – h)^2 + k) if needed