Which factoring method would be best to factor x^2 - 9?

a perfect square trinomial method
b greatest common factor method
c trial and error
d difference and squares

  D.  difference of squares

Step-by-step explanation:

Both of the terms x^2 and 9 are squares, so their difference is the difference of squares. The factorization of that is a "special form" that can be usefully memorized.

  a^2 -b^2 = (a -b)(a +b)

  x^2 -9 = (x -3)(x +3)

4

step-by-step explanation:

32

step-by-step explanation: