Factor completely x2 + 16.
(x + 4)(x + 4)
(x + 4)(x − 4)
prime
(x − 4)(x − 4)

The factors of x^2 + 16 are (x - 4i) and (x + 4i).

Step-by-step 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.

think about it deeply and passionately about this property

i am sorry