#### Answer

$16x^2+4$

#### Work Step by Step

The perimeter of a square is 4 times any side value since the sides are equal. So the expression to solve is $4(4x^2+1)$.
Distribute the 4 to each term:
$16x^2$
and
$4$
$16x^2+4$
Since we do not know the value of x and this is not an equation, this is the final answer.