#### Answer

$ (1-2n)(1+2n)$

#### Work Step by Step

The given expression can be written as:
$=1^2-(2n)^2$
RECALL:
A difference of two squares can be factored using the formula:
$x^2-y^2=(x-y)(x+y)$
Use the formula above with $x=1$ and $y=2n$ to obtain:
$= (1-2n)(1+2n)$