Answer:
A
Step-by-step explanation:
A) a single variable has an imaginary 1 in front of it, therefore
8d + 1d
= 9d
B) factor 3 into each party in the parenthesis, which gives
d + (3d + 9d)
= 13d
C) factor 2d into each party in the parenthesis
8d + 10d
= 18d
therefore the only equation that gives 9d is option A
