So the length is 4w-10 and the width is just w, the area (the cover) is
(4w-10)(w)=500. So when you multiply it out you get 4w²-10w=500. When you solve for that you get that w is 12.5, -10 but since it is a measurement, it needs to be positive so w=12.5. Substituting that back into the equation, ((4)(12.5)-10)=40. So 40+40+12.5+12.5= 95.
