How do I solve this?

Question

This problem seems like it would be pretty straightforward, however, it is proving to be quite difficult for me to solve. I am having trouble setting it up because whenever I set it up and solve, I end up with the wrong answer. Super frustrating! If someone could post a step-by-step response showing how to solve this that would really help me out. Thanks!

 

Problem:

A rectangular yard has area 96 square feet. If the width of
the yard is 4 feet less than the length, what is the perimeter,
in feet, of the yard? 

 

Answers: 

A. 40

B. 44

C. 48

D. 52

 

 

Answer 1

Let x = the length and x-4 = the width:

 

Area = (length)(width)

96 = x(x-4)

96 = x² - 4x

0 = x² - 4x - 96

0 = (x-12)(x+8)

 

x = 12 and -8.  Since you can't have a negative length, x = 12.

 

Perimeter = 2(length) + 2(width)

Perimeter = 2x + 2(x-4)

Perimeter = 2(12) + 2(12-4)

Perimeter = 40