Question 753059
Let W = the width of the rectangle
Let L = the length of the rectangle
The problem most of my students have is to remember the formula for the perimeter, p. It is
(1) p = 2*L + 2*W, do you have this?
Next write the expression for length as given by the problem statement, namely that the lenght is 4 less than twice the width or
(2) L = 2*W - 4. Do you have that?
Now put L of (2) into (1) and get
(3) p = 2*(2*W - 4) + 2*W 
Now set (3) to the perimeter of 34 inches and get
(4) 2*(2*W - 4) + 2*W = 34
Now simplify (4) to obtain
(5) 4*W - 8 + 2*W = 34 or
(6) 6*W = 34 + 8 or
(7) 6*W = 42 or
(8) W = 42/6 or
(9) W = 7
Then from (1) we get
(10) L = 2*7 - 4 or
(11) L = 10
Let's check these values.
Is (2*10 + 2*7 = 34)?
Is (20 + 14 = 34)?
Is (34 = 34)? Yes
Answer: The lenght of the rectangle is 10 inches and the width is 7 inches.