Answer:
The length is 20 units. The width is 8 units.
Explanation:
The width is an unknown, so we will let W = the width.
The length is also an unknown, but we know the length is 12 units more than the width, so the length is L = W + 12.
The perimeter is 7 times the width. P = 7W
The perimeter is also the sum of two lengths and two widths.
P = 2L + 2W
7W = 2(W + 12) + 2W
7W = 2W + 24 + 2w
7W = 4W + 24
3W = 24
W = 8
The width is 8 units.
L = W + 12
L = 8 + 12 = 20
The length is 20 units.