Question 470268
Half of the perimeter is 9 feet and its equal L+W=9. Let the W=x, then L=9-x, and the area is equal A=LxW, substituting we get:

{{{20=x(9-x)}}} write this equation in standard form {{{x^2-9x+20=0}}}, and solve 

it by factoring {{{(x-5)(x-4)=0}}}. Set to zero each factor to find the roots:

x-5=0 <=> x=5, and x-4=0 <=> x=4.

Answer:The width of the rectangle is 4 feet and its length  5 feet.