Respuesta :

8d + 4d - 5d - 4 = 3d
12d - 5d - 4 = 3d
7d - 4 = 3d
7d = 3d + 4
4d = 4
d = 1
8d+4d-5d-4=3d
 7d-4=3d
 7d-3d=4
 4d=4
 d=1