What number would go in the blank when solving the equation by completing the square?

Question

What number would go in the blank when solving the equation by completing the square?

x² + 16x         = 17 +        

Answer 1

It's one-half of the "b" value, squared.

So it's (16/2)² = 64

x² + 16x + 64 = 17 + 64

You can factor the left side easily and find the value of x.