Okay, here we have this:
Considering that the area of a rectangle is:
Area=length*width
Replacing we obtain:
300=(5+x)*x
300=5x+x²
0=5x+x²-300
0=(x-15)(x+20)
This mean that:
x-15=0 or x+20=0
x=15 or x=-20
And considering that the distances are positive we are left with the first solution, x=15; this mean that:
Width=15 yd
Length=(15+5) yd=20 yd.
Finally we obtain that the width is 15 yd and length is 20 yd.
