Question

The length of a rectangle is one unit shorter than one-sixth of the width, x.

Answer 1

Lets say that y represents length and x width.
From the text we can write:
y=x/6 - 1

Perimeter we calculate: 
P = 2*x + 2*y

now we use y equation from above and put it in perimeter equation:

P = 2*x + 2*(x/6 - 1)
P = 2*(7x/6 - 1)
P = 7x/3 - 2