The length of a rectangular playing field is 5 meters less than twice its width. if 230 meters of fencing goes around the field, find the dimensions of the field.

If the length is 5 less than twice the width, let let length be L and width be W.
The equation is L = W2-5. So 2L + 2W = 230.

Because L can be written as W2-5, you can write the entire equation as 
2(W2-5) + 2W = 230
Simplified, that is 6W-10=230
Add 10 to both sides for
6W=240. Divide both sides by 6 and get
W=40
So the width equals 40 meters, and the length equals 75 meters.