Question 45168
Some variables I'll use:

l = length
w = width
p = perimeter

First, we have that
{{{l = 2w + 2}}}

And the formula for a perimeter calculation, in general, is l+l+w+w, or:
{{{p = 2l + 2w}}}

Substituting 34 for p:
{{{34 = 2l + 2w}}}

Substituting 2w + 2 for l:
{{{34 = 2(2w + 2) + 2w}}}


And now we solve for the width:
{{{34 = 4w + 4 + 2w}}}
{{{34 = 6w + 4}}}
{{{30 = 6w}}}
{{{5 = w}}}

If l is 2w+2, substituting w for 5 gives us:

{{{l = 2w + 2 = 2*5 + 2 = 10 + 2 = 12}}}

Therefore, the length is 12 inches and the width, 5 inches.