x²–14x To the side: Multiply -14 by, getting -7 Square -7, getting (-7)² or +49 Make the zero sum +49-49, and add that to the given expression: x²-14x+49-49 Factor the first three terms (x-7)(x-7)-49 Write that as (x-7)²-49 Put a 1 in front of the binomial squared: 1(x-7)²-49 That is in the form a(x+b)+c a=1, b=-7, c=-49 Edwin