Respuesta :

I'm not quite sure if this is correct but 

d = 1 
8d +d = 9d 

the you have 1 and 7 + 1 = 8 

hope this helps :)

Answer:

Step-by-step explanation:

Sample Response: Use the associative property to move the parentheses, and the expression becomes (d + 8d) + 1 + 7. Combine like terms, and the expression becomes 9d +8. Use the commutative property to change the order of the terms, and the expression becomes 8 + 9d.