Question 317068
x^2 - 8x + 16 - 9y^2 

Separate into two polynomials and factor individually.

x^2 - 8x = x(x - 8) after factoring.

16 - 9y^2 = (4 - 3y)(4 + 3y) after factoring.

Answer: x(x - 8)(4 - 3y)(4 + 3y)

Notice that the answer yields 4 factors.  Do you see all four factors?