I think you need only an answer without expanation so let's start.
a)

b)
D= it's is true because ox equals 3*2x
Answer:
9x2+5x
Step-by-step explanation:
combine like terms
Since there are six numbers, on average 1,2,or 3 will come up 50 percent of the time and 4,5, and 6 will also come up 50 percent
I think it the 3 and 4 one ... sorry if I’m wrong