I'm not really sure how to start this.

How many times does this cross the x-axis:

a) x^2 + 12x + 36 = 0

Does the 0 make a difference, or would I just see what multiplys to get 36 and adds to get 12 and then factor it that way? This is important and I'm totally lost, I can't remember and I can't find any notes whatsoever on how to do equations that = 0, or equations that ask how many times they cross the x-axis.

Any help would be appreciated!