Question 848410
<pre>
x²–14x

To the side:
Multiply -14 by {{{1/2}}}, 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</pre>