Complete the square: x^2 -12x. Which of the following is the correct perfect-square trinomial?

Question

the answers are:
a.) x^2 +22x+121
b.) x^2 -10x+25
c.) x^2 -20x+44
d.) x^2 -12x+36
This is tough because the answers could be a.) b.) and d.)
I am not sure which to choose.

Answer 1

You are seeing something the rest of us isn't. Only one answer has -12x in it.

Answer 2

To complete the square, you divide the number before the x by 2, square it, and add it to the end. The answer is d.