Respuesta :

Answer:

-9d + 10d = 9

10d - 9d   = 9

          d    = 9

Step-by-step explanation:

Correct me if I’m terribly wrong Answer:

-9d = -10d + 9

+10d +10d (Add 10d on both sides)

1d = 9

Divide by 1 on both sides

d=9