Question 1044743
width=x
length=x+12, the width is 12 feet less, the length is 12 feet more.  I could make length x and width x-12, but I'd rather deal with + than -.  You get the same answer.
x(x+12)=540.  LxW=area
x^2+12x-540=0
(x+30)(x-18)=0
x=-30, 18.  Only the second answer makes sense
width is 18 feet and length is 30 feet.