if the perimeter of the rectangle is 80 yd find its length and width

Answer 1

2L + 2W = P = 80

L+W = 40

Length = 40 - Width

Width = 40 = Length

0<L<40 yards

0<W<40 yards

You usually have another piece of information to narrow it down to a unique solution, such as

length is 3 yards more than the width

then L=3+W

L+W = 40

3+W + W = 40

2W = 40-3 = 37

W = 37/2 = 18.5 yards

L = 3+ W = 21.5 yards