Question 593776
<pre>
   x² – 16 

(x + 4)(x - 4)

Check it by FOILing it out and seeing if you get the original.

(x + 4)(x - 4) = x² - 4x + 4x - 16.

That simplifies after cancelling the -4x and the +4x to

x² - 16, which is what you started with, so it is correct.

Edwin</pre>