Heyo, I don't get where she got the 49 from, can someone help?

Answer:Instructions below
Step-by-step explanation:
This is completing the square, so what happened was that -14 was divided, then squared, to find a perfect square. To find the third term, you have to divide it by two then square it, then add it to the other side to balance the equation out.
-14/2 = -7^2 = 49 This applies to every question in which you have to complete the square