#### Answer

$P=2l+32/l$
Domain: $l>0$

#### Work Step by Step

We know that the area of the rectangle is $16\ m^2$, so:
$lw=16$
The perimeter of the rectangle is:
$P=2l+2w$
We need the perimeter as a function of only one side, so we eliminate $w$:
$w=16/l$
$P=2l+2(16/l)=2l+32/l$
The domain is $l>0$, since the length must be positive and non-zero.