Let L = length
Let W = width.
2L + 2W = 64 meters.
W = L - 8
L = ???
W= ???
Divide the first equation by 2.
L + W = 64/2
L + W = 32
Substitute for the width.
L + L - 8 = 32 Combine like terms on the left
2L - 8 = 32 Add 8 to both sides.
2L = 32 + 8
2L = 40 Divide by 2
L = 40/2
L = 20
The width = 20 - 8 = 12 because the width is 8 less than the length.
Check
20 * 2 + 12*2 = ? 64
40 + 24 = ?64
64 = 63 They do check.