Answer:
The factors of x^2 + 16 are (x - 4i) and (x + 4i).
Explanation:
That'd be x^2 + 16, not x2 + 16.
First, an easier example: x^2 - 16 factors into (x - 4)(x + 4).
Note how (-4)(4) = -16.
The corresponding factors of x^2 + 16 are (x - 4i) and (x + 4i).
We can check this result through multiplication: (x - 4i)(x + 4i) = x^2 - 4ix + 4ix - 16(-1), or x^2 + 16.