factor (x^2-9)^2
Let's factor in ℝ: (x2 -9)2
Let's factorize in ℝ: x2 -9
For x2 -9, we recognize a difference of two squares: x2 -32. Apply a2 -b2 = (a -b)·(a + b), with a = x and b = 3
Factors identified: (x + 3)·(x -3)
▶Factored expression:   (x + 3)2·(x -3)2