Question

Factor: x2 - 16

Answer 1

use difference of two squares
a^2 - b^2 = (a+b)(a-b)
put a=x and b=4
you'll get x^2 - 4^2 = (x+4)(x-4)

Answer 2

x^2 - blah = (x+sqrt(blah))(x-sqrt(blah))

Answer 3

That's my formal math language in action lol.