l + w + l + w = 56
2l + 2w = 56
2w = 56 - 2l
(2w) + (2w) + (l + 8) + (l + 8) = 82
2(2w) + 2(l + 8) = 82
2(56 - 2l) + 2l + 16 = 82
112 - 4l + 2l + 16 = 82
112 - 82 + 16 = 4l - 2l
46 = 2l
46/2 = l
23 = l
2w = 56 - 2l
2w = 56 - 2(23)
2w = 56 - 46
2w = 10
w = 10/2
w = 2
length(l) = 23 m and width(w) = 2 m