the perimeter of a rectangle if the width is w centimeters and the length is 3 cm more than twice the width

L being the length, W being the width.

So:

if the Length is 8cm more than twice the width, we have:

2W+8

so it's:

perimeter of a rectange = 2(2W+8)+2W

You asked me not to simplify it, so that should be your answer.