Respuesta :

P = 2(L + W)
P = 418
L = 3W + 9

418 = 2(3W + 9 + W)
418 = 2(4W + 9)
418 = 8W + 18
418 - 18 = 8W
400 = 8W
400/8 = W
50 = W <=== width is 50 cm

L = 3W + 9
L = 3(50) + 9
L = 150 + 9
L = 159 <=== length is 159 cm