Problem: If the pool's perimeter is 126 meters, what are its dimensions?
Length is 6 meters less than twice its width
L = 2W - 6
P = 2L + 2W
126 = 2(2W - 6) + 2W
126 = 4W - 12 + 2W
126 = 6W - 12
6W - 12 + 12 = 126 + 12
6W = 138
6W/6 = 138/6
W = 23
L = 2W - 6
L = 2(23) - 6
L = 46 - 6
L = 40
Answer: length = 40 meters, width = 23 meters