Complete the square to form a perfect square trinomial x^2-14x+

x^2 - 14x + 49

Explanation:

1) Divide the coefficient of x by 2:

14 / 2 = 7

2) so you have to add 7^2 = 49

x^2 - 14x + 49

3) that trinomial is equivalent to:

=> (x - 7)^2

4) prove that using the formula (a - b)^2 = a^2 - 2ab + b^2

(x - 7)^2  = x^2 - 14x + 49

Then you have to add 49 to complete the square. and form a perfect square trinomial.